数学

求任意一组数字的平均值，以及总和、个数、最小值和最大值。

计算组合数 nCr——从 n 个物品中选择 r 个且顺序无关的方式数。

用这个指数计算器将任意底数升至任意次幂，支持负指数、分数指数和小数指数。

对两个分数进行加、减、乘或除运算，并即时得到化简后的结果及其小数值。

使用欧几里得算法求一组整数的最大公约数 (GCD/HCF) 和最小公倍数 (LCM)。

计算任意正数以任意底的对数，外加自然对数 (ln) 和常用对数 (log₁₀)。

计算旧值与新值之间的百分比增减，以及绝对差值。

快速计算百分比：Y 的 X%、一个数是另一个数的百分之几，以及百分比变化。

求解形如 a:b = c:d 的比例中的缺失值，并将任意比率化简为最简形式。

由任意两个已知量（直角边、斜边或锐角）求解直角三角形，包含面积和周长。

求一个数的平方根、立方根或任意 n 次方根，包括负数的实奇次方根。

Find the determinant, trace, rank, eigenvalues and inverse of any 2×2 matrix in one step, with an animated transformation.

求正弦波 y = A sin(Bx + C) + D 的振幅、周期、相移和垂直移动。

Calculate the bitwise AND of two integers and see the result in decimal, binary, and hexadecimal.

Calculate the antilogarithm (inverse log) of any value in any base: find b^x, 10^x (antilog₁₀), and e^x (antiln).

计算曲线 y = f(x) 在 x = a 到 x = b 之间的弧长。

Calculate arccos(x) — the inverse cosine of a value — in both degrees and radians. Input must be in [−1, 1].

Calculate arcsin(x) — the inverse sine of any value between −1 and 1 — in both degrees and radians.

Calculate arctan(x) — the inverse tangent of any real number — in degrees and radians, with the complementary arccot.

计算区间 [a,b] 上两函数 f 和 g 之间围成的面积。

使用精确数值积分计算 a 到 b 之间曲线下方的面积。

计算函数在两个 x 值 a 和 b 之间的平均变化率（割线斜率）。

利用积分均值定理，求函数在区间 [a,b] 上的平均值。

以精确大整数精度对超大整数进行加、减、乘、除、取模或幂运算。

在固定宽度内将整数向左或向右旋转 k 位。离开一端的位从另一端回绕。

使用位掩码操作在整数中的位置 k 处设置、清除、翻转或测试单个位。

将整数逻辑或算术地向左或向右移动 k 位。以十进制、二进制和十六进制显示移位结果。

Perform bitwise AND, OR, XOR, NAND, NOR, XNOR and NOT on two integers within a 4, 8, 16, 32 or 64-bit register, with binary and hex output.

对两个整数计算按位 AND、OR、XOR、NOT（以及 NAND/NOR/XNOR）。以十进制、二进制和十六进制查看结果。

为两个布尔变量在所选运算符（AND、OR、XOR、NAND、IMPLIES、IFF）下构建真值表。

计算第 n 个卡特兰数，统计平衡括号、二叉树、路径和三角剖分的数量。

由半径和圆心角计算圆扇形面积，显示为整个圆的一个扇片。

为任意起始数生成科拉兹（3n+1）序列，并计算到达 1 的步数。

统计多重集选择：从 n 种类型中可重复选择 r 个，即 C(n+r-1, r)。

Calculate the cosine of any angle in degrees or radians — plus sine, tangent and cotangent, instantly.

Calculate the cosecant (csc) of any angle in degrees or radians. Shows csc(θ) = 1/sin(θ), all six trig functions, and a step-by-step solution.

Calculate cosh(x) — the hyperbolic cosine — plus sinh(x) and tanh(x), with a graph of the characteristic catenary curve.

Calculate the cotangent cot(θ) = cos(θ)/sin(θ) in degrees or radians — with sin, cos, tan and a graph of the cotangent function.

通过加减完整圆周，求任意给定角的正负同终边角。

Calculate volume, total surface area, lateral surface area, space diagonal and face diagonals of a cuboid (rectangular box) from length, width and height.

Calculate the arc length and area of a cycloid arch traced by a rolling circle of radius r. Shows parametric equations and animated curve plot.

Calculate the area, perimeter, circumradius, inradius, and diagonals of a regular decagon (10-sided polygon) from any known measurement.

Convert fractions to decimals (including repeating decimal detection) and decimals to simplified fractions, with step-by-step working.

使用精确原函数计算常见函数从 a 到 b 的定积分。

在角度与弧度之间即时转换，并将结果以 π 的简洁倍数形式显示。

计算任意数各位数字之和，并通过反复求和得到其数字根。

计算函数 f(x,y) 在某点沿指定方向向量的方向导数。

计算欧拉函数 phi(n)：从 1 到 n 中与 n 互质的整数个数。

Find the prime factorisation, all divisors, number of divisors and sum of divisors for any positive integer up to 1,000,000.

计算任意非负整数的阶乘 n!，即从 1 到 n 所有整数的乘积。

列出整数的所有因数（除数），计算因数个数、总和，并配对每个因数与其互补因数。

求第 n 个斐波那契数，列出前 n 项数列，并计算累积和。

Expand (ax + b)(cx + d) using the FOIL method with full step-by-step working — First, Outside, Inside, Last — and get the simplified polynomial.

Find the greatest common divisor of two integers using the Euclidean algorithm, with every step shown.

Find the greatest common factor (GCF) of two or more integers — lists all common factors and simplifies fractions.

求二元函数在某点的梯度向量及其模长。

计算 n 个顶点完全图的边数：无向图为握手数 n(n-1)/2，有向图为 n(n-1)。

求两个等长二进制（或十六进制）字符串的汉明距离：位不同的位置数。

对两个十六进制或二进制数进行加减运算，并同时以十六进制、二进制和十进制显示结果。

计算某值的反正弦、反余弦或反正切，并以度和弧度两种形式给出所求角度。

应用余弦定理，由三角形两边及夹角求第三边，或由三边求角。

使用正弦定理，由已知边角对求三角形的未知边或角。

Find the Least Common Denominator (LCD) of two or three fractions instantly, with step-by-step multipliers and a visual breakdown.

Find the Least Common Multiple (LCM) of two or three integers using the GCD / Euclidean algorithm, with step-by-step working.

通过对两侧数值探测，估计函数在 x 趋近某值时的极限。

Calculate the logarithm of any positive number in base 10, natural (e), base 2, or a custom base instantly.

Validate any credit card, IMEI, or ID number using the Luhn algorithm checksum — with a step-by-step walkthrough.

求函数在区间 [a,b] 上的绝对最大值和最小值。

Calculate the arithmetic, geometric and harmonic mean of any list of numbers — enter values separated by commas.

用中点法则以 n 个矩形近似定积分。

使用快速平方取幂法和大整数，高效计算 (base^exponent) mod m。

求一个数的模乘逆元，即满足 a*x 与 1 同余于 mod m 的 x。

求除法的余数和商，提供截断、向下取整和欧几里得三种取模变体以处理负数。

从初始猜测值出发，用牛顿迭代法求函数的根。

Calculate the bitwise NOR of two integers — NOT(A OR B) — and see the result in decimal, binary, and hexadecimal.

在二进制、八进制、十进制、十六进制及 2 到 36 进制之间转换数字。

在 2 到 36 进制之间转换数字（二进制、八进制、十进制、十六进制等），支持所有数字字符。

将任意整数拼写为英文，例如 1234 变为 one thousand two hundred thirty-four。

用中心差分法求函数在某点处的导数，无需符号代数运算。

在选定位宽下，并排显示有符号整数的原码、反码和补码表示。

Compute the bitwise OR of two integers in decimal, binary or hex, with a full bit-by-bit breakdown.

计算二进制字的偶校验位和奇校验位，并统计其中的 1 位数，用于错误检测。

在某点处数值计算二元函数 f(x,y) 的偏导数。

生成帕斯卡三角形的任意一行——k = 0 到 n 的二项式系数 C(n,k)。

通过将一个数与其真因数之和比较，检验它是完全数、盈数还是亏数。

计算排列数 nPr = n!/(n-r)!——从 n 个元素中有序选取 r 个元素的排列数。

计算允许重复时的排列数：从 n 个符号中有序选取 r 个位置共 n^r 种方案。

Approximate π using Nilakantha, Gregory–Leibniz or Machin series — see convergence, error and correct decimal places for any number of terms.

应用鸽巢原理：求最满箱子中有保证的最小数量，以及迫使达到目标数量所需的物品数。

将极坐标 (r, theta) 转换为直角坐标 (x, y) 并绘制结果点。

计算整数中置位（汉明重量）的数量和位长度，并检查其是否为 2 的幂。

Explore the Potato Paradox: calculate how much weight a batch loses when its water percentage drops slightly.

求 n 元集合幂集中子集的数量：共 2^n 个，另加真子集和非空子集的数量。

将任意整数分解为质因数并显示指数形式，例如 360 = 2^3 x 3^2 x 5。

检验任意整数是否为质数，并使用直到平方根的快速试除法查看其质因数分解。

使用模和 atan2 角将直角坐标 (x, y) 转换为极坐标形式 (r, theta)。

计算任意角度的参考角，并以度数或弧度显示其所在象限。

计算函数在区间上的左端点、右端点或中点黎曼和。

将任意数四舍五入到选定的小数位数，或四舍五入到最接近的 10、100 或 1000，并给出向下取整和向上取整值。

Generate RSA public and private keys from two primes, then encrypt and decrypt an integer message — step by step.

在小数和科学记数法之间相互转换，显示尾数、指数和标准形式。

Calculate sec(θ) — the secant function — in degrees or radians, plus all six trig function values at the same angle.

求函数在某点的二阶导数，并判断该处是向上凹还是向下凹。

计算您输入的两个集合的并集、交集、差集和对称差，并显示元素数量。

用辛普森法则（抛物弧线）近似定积分，实现高精度。

Calculate sin(θ), cos(θ), tan(θ) and cot(θ) for any angle in degrees or radians instantly.

一步求出任意度数或弧度角的正弦、余弦、正切及其倒数。

Calculate sinh(x), cosh(x), tanh(x) and coth(x) for any real x. Verifies the identity cosh²−sinh²=1 and plots the curve.

计算第二类斯特林数 S(n,k)：将 n 件物品划分为 k 个非空子集的方案数。

Count the subsets of a set with n elements: total 2ⁿ subsets, proper subsets, non-empty subsets and C(n,k) subsets of any size k.

计算曲线绕 x 轴从 a 到 b 旋转一周所生成的曲面面积。

Compute singular values, condition number, rank, Frobenius norm and spectral norm of a 2×2 matrix via SVD.

Calculate tan(θ) for any angle in degrees or radians — plus sin, cos, cot, sec and csc, with a plotted tangent curve.

求函数在给定点 x = a 处切线的方程。

Calculate tanh(x) — the hyperbolic tangent — plus sinh(x), cosh(x) and the derivative sech²(x), with the characteristic S-curve plot.

对函数在中心 c 处求 Taylor 多项式并与精确值对比。

Calculate sin, cos, tan, cot, sec and csc for any angle θ in degrees or radians, with quadrant and reference angle.

用梯形法则将积分区间分成 n 个子区间，估算曲线下的面积。

计算第 n 个三角数（1+2+...+n）并查看三角数序列。

Calculate all six trigonometric functions — sin, cos, tan, csc, sec, cot — for any angle in degrees or radians.

在给定角度处对所选三角恒等式的两侧分别求值，数值验证其成立。

在 8、16、32 或 64 位下将有符号十进制数转换为二补码二进制数及反向转换，并显示可表示范围。

获取任意角度在单位圆上的精确 (cos, sin) 坐标，并在圆上绘制该点。

Calculate 2D vector magnitude, dot product, 2D cross product, angle between vectors and resultant sum — with an animated vector diagram.

求曲线绕 x 轴旋转所形成的旋转体体积（圆盘法）。

Calculate A XOR B for any two integers up to 32 bits. Shows the result in decimal, binary and hex with a step-by-step bit breakdown.

Calculate the straight-line Euclidean distance between two points on a plane, plus midpoint, slope and angle.

Calculate a triangle's area from all three side lengths using Heron's formula, plus angles, altitudes, inradius and circumradius.

Solve a 30-60-90 special right triangle from any one side. Instantly get the short leg, long leg, hypotenuse, area and perimeter.

Solve a 45-45-90 isosceles right triangle from either side. Get the two equal legs, hypotenuse, area, and perimeter instantly.

Add, subtract, multiply and divide complex numbers in a+bi form; also computes modulus and argument for each number.

Solve a triangle from all three angles (AAA). Optionally supply one side to scale the triangle and find all sides, area, perimeter, and radii.

Solve a triangle from two angles and a non-included side (AAS) — find all sides, angles, area, perimeter, inradius, and circumradius via law of sines.

Calculate the absolute change (net difference) and percentage change between two values instantly.

Solve absolute value inequalities of the form |ax + b| < c, ≤, >, ≥ and display the solution set on a number line.

Check if a triangle is acute and calculate its area, all angles, perimeter, inradius and circumradius from the three side lengths.

Add or subtract two polynomials up to degree 3 by entering their coefficients — shows the result and a step-by-step like-terms solution.

Add or subtract two fractions with different denominators — finds the LCD, converts, computes, and simplifies step by step.

Add two fractions with any denominators — automatically finds the LCD, converts both fractions, and simplifies the result step by step.

Add two or three numbers instantly and see the sum, the full arithmetic expression, and a number line showing every addend.

Compute the adjoint (adjugate) matrix and determinant for any 2×2 or 3×3 matrix, with step-by-step cofactor working shown.

Calculate the inverse tangent (arctan) of any real number — returns the angle in radians, degrees and gradians.

Calculate the area, circumference and diameter of a circle from its radius — using the formula Area = π × r².

Calculate the area, perimeter and midline of a trapezoid from its two parallel sides and height using Area = ½ × (a + b) × h.

Calculate the area of an oblique (non-right) triangle from two sides and their included angle using ½ × a × b × sin(C).

Calculate the area and all angles of an obtuse triangle from its three side lengths using Heron's formula.

Solve a triangle from two angles and the included side (ASA). Calculates all sides, the third angle, area, perimeter and height.

Verify the associative property for addition or multiplication with any three numbers — shows both groupings step by step.

Calculate the simple average (arithmetic mean) of up to five percentage values — useful for grades, survey results, growth rates and more.

Convert any decimal integer (1–215,999) to its Babylonian cuneiform numeral representation in base-60 with a step-by-step decomposition.

Find the base of a triangle from its area and height, or from two sides and the included angle using the law of cosines.

Compute Bessel functions of the first kind J₀(x), J₁(x) and J₂(x) using the power series, and plot all three curves from x = 0 to 15.

Interpolate a value at any (x, y) point inside a 2D rectangular grid using the four corner values — step-by-step.

Add two binary numbers and see the sum in binary, decimal, and hex with a step-by-step carry trace.

Divide two binary numbers to find the quotient and remainder. See results in binary and decimal with the verification N = Q × D + R.

Convert decimal fractions to binary or binary fractions to decimal. Shows repeated ×2 steps and place-value bit contributions.

Multiply two binary numbers using the shift-and-add method. See partial products, the binary result, and the decimal equivalent.

Perform AND, OR, XOR, NOT, NAND, NOR, XNOR on binary number inputs. See results in binary, decimal, and hex with bit-by-bit steps.

Subtract two binary numbers using the two's complement method. See the result in binary, decimal, and hex with step-by-step working.

Calculate the binomial coefficient C(n, k) — the number of ways to choose k items from n — with Pascal's triangle row visualised.

Multiply two binomials (ax + b)(cx + d) using the box (grid) method with step-by-step workings.

Convert a Cartesian point (x, y) to polar coordinates (r, θ) — get the radius and angle in degrees and radians instantly.

Calculate the arc length, catenary parameter, and shape of a hanging cable or chain from its span and midpoint sag.

Calculate the ceiling ⌈x⌉ of any number — the smallest integer ≥ x — plus floor, round and truncate for comparison.

Find the center (h, k) of any ellipse from its general conic equation Ax² + Bxy + Cy² + Dx + Ey + F = 0, including tilted ellipses.

Calculate the center of mass (x̄, ȳ) for a system of up to three point masses in 2D using x̄ = Σ(mᵢxᵢ)/Σmᵢ.

Calculate the central angle of a circle from radius and arc length. Get angle in degrees and radians, sector area, and chord length.

Find the centroid (geometric centre) of 2, 3 or 4 points in 2D space — the arithmetic mean of all x and y coordinates.

Find the centroid (intersection of medians) of a triangle from its three vertex coordinates, plus side lengths, area and median lengths.

Compute log_b(x) for any positive base b and argument x using the change-of-base formula: log_b(x) = ln(x)/ln(b).

Find the characteristic polynomial and eigenvalues of a 2×2 matrix. Enter a, b, c, d and get det(A − λI) = 0 with all roots shown.

Solve a system of three simultaneous congruences using the Chinese Remainder Theorem (CRT) with step-by-step working.

Compute the Cholesky decomposition L of a 2×2 symmetric positive-definite matrix A so that L × Lᵀ = A.

Find the center (h, k) and radius of a circle passing through any three non-collinear points.

Calculate circle diameter from radius, area, or circumference — plus area, circumference, and radius from any single input.

Write the equation of a circle in standard form (x−h)²+(y−k)²=r² and general form from its center and radius.

Apply all circle formulas at once: area, circumference, arc length, sector area, chord length, and segment area from radius and angle.

Calculate the arc length of a circle from its radius and central angle in degrees or radians.

Calculate the area, circumference, diameter and sector values of a circle from its radius in any unit.

Calculate the circumference, arc length, chord length and sector or segment perimeter of a circle.

Apply circle theorems to find inscribed angles, arc length, chord, sector area and cyclic quadrilateral angles from a central angle.

Find the circumcenter coordinates and circumradius of a triangle — the centre and radius of the unique circle passing through all three vertices.

Find the circumference and area of a circle from its radius, diameter, or area using C = 2πr and A = πr².

Calculate the circumference of a circle from its radius or diameter using C = 2πr.

Convert circumference to diameter using d = C ÷ π. Also finds the radius and enclosed area.

Find the radius of a circle from its circumference using r = C ÷ (2π).

Calculate the circumradius and circumcircle area of a regular polygon or any triangle.

Enter three side lengths to classify a triangle by sides (equilateral, isosceles, scalene) and by angles (acute, right, obtuse), plus all angles and area.

Find the angle between the hour and minute hands of a clock at any time. Instant clock-hand angle calculator with animated clock face.

Compute the determinant of a 3×3 matrix by Laplace cofactor expansion along row 1, with full step-by-step working.

Find all six cofunction pairs — sin/cos, tan/cot, sec/csc — for any angle in degrees or radians.

Calculate how many times a rolling coin rotates when circling a fixed coin — including the paradoxical extra rotation.

Find the column space (range) of a matrix: dimension, rank, nullity, and basis vectors — via row reduction for matrices up to 4×4.

Find the least common denominator (LCD) of two fractions and convert both to equivalent fractions so they can be added or compared.

Find all common factors (divisors) of two numbers and the greatest common factor (GCF), with step-by-step Euclidean algorithm.

Find the least common multiple (LCM) of two numbers and list the first N common multiples — with formula, GCF, and animated sequence.

Compare two fractions and find which is greater, equal or smaller — with cross-multiplication steps, common denominators and decimal equivalents.

Find compatible numbers (friendly round numbers) for quick mental arithmetic and see how close the estimate is to the exact answer.

Find the complement of any angle (90° − θ), plus its supplement, explementary angle and all six trig cofunction identities.

Add, subtract, multiply or divide two complex numbers and find their modulus, argument and Argand-diagram representation.

Convert a complex number a + bi to polar form r∠θ — find the magnitude and argument instantly.

Convert polar form r∠θ to rectangular form a + bi using r·cos(θ) and r·sin(θ).

Convert a + bi to trigonometric form r(cos θ + i·sin θ) — find modulus and argument instantly.

Find all n complex roots of any complex number a + bi using De Moivre's theorem — roots plotted on the unit circle.

Condense a sum or difference of two logarithms into a single log using the power, product and quotient rules, with step-by-step working.

Compute the spectral and Frobenius condition numbers of a 2×2 matrix from its singular values, with an interpretation of numerical stability.

Calculate the lateral and total surface area of a cone from its base radius and height, including slant height and base area.

Calculate the volume of a cone from its base radius and height: V = (1/3)·π·r²·h, plus slant height, base area and surface area.

Explore properties of circles, ellipses, parabolas and hyperbolas — equations, eccentricity, foci, asymptotes and plotted curves.

Find the complex conjugate of z = a + bi: flip the sign of the imaginary part to get a − bi, with modulus, argument and modulus squared.

Find the sum, mean, range and product of k consecutive integers starting at n. Visualise the sequence on a number line.

Compute the discrete linear convolution of two finite sequences using the standard sum-of-products formula.

Calculate the Euclidean and Manhattan distance between two 2D points, plus midpoint, slope and Pythagorean diagram.

Enter two coordinate points and get slope, distance, midpoint, line equation, y-intercept and quadrant — with a live coordinate grid plot.

Find the corner point (vertex) where two constraint lines intersect using Cramer's rule — a key step in the linear programming corner-point method.

Calculate cos(2θ) using all three double-angle identities, plus sin(2θ) and tan(2θ), for any angle in degrees or radians.

Calculate cos⁻¹(x) — the inverse cosine — in degrees and radians for any cosine value from −1 to 1.

Compute cosine similarity between two vectors of any dimension: dot product over product of magnitudes. Returns similarity, angle, and cosine distance.

Solve any triangle with the law of cosines. Enter two sides and the included angle (SAS) or all three sides (SSS) to find the missing side, all angles, area and perimeter.

Calculate the area of a crescent (lune) formed by two overlapping circles of different radii and a given centre offset.

Solve a proportion a/b = c/x for the unknown x using cross multiplication. See every step of the working.

Calculate the cross-sectional area of circles, rectangles, triangles, ellipses, and hollow tubes — used in engineering and geometry.

Calculate the cube root of any number (positive, negative or zero) with step-by-step working and a y = ∛x graph.

Calculate the total surface area of a cube from its side length. Instantly get face area, perimeter and space diagonal.

Find the volume, surface area and diagonal of a cube from its side length. Covers space diagonal, face diagonal and total edge length.

Calculate the volume of a cube from its side length using V = s³. Also shows surface area and space diagonal instantly.

Calculate the volume of a cylinder in cubic feet from diameter and height. Also converts to cubic yards, cubic meters, liters and US gallons.

Calculate the volume of a cylinder in cubic inches from diameter and height. Converts instantly to cubic feet, liters and US gallons.

Calculate the volume of a cylinder in cubic yards from its diameter and depth in feet. Ideal for circular concrete pads, ponds and footings.

Calculate the total and lateral surface area of a rectangular cuboid (box) from its length, width and height using SA = 2(lw + lh + wh).

Calculate the volume, surface area and space diagonal of a rectangular cuboid (box) from its length, width and height.

Calculate McCabe's cyclomatic complexity (M = E − N + 2P) to measure code complexity and the minimum test paths needed.

Calculate a cylinder's base circumference (C = 2πr), diameter and lateral surface area from the radius and height.

Find a cylinder's diameter from its circumference (d = C ÷ π) or from its radius (d = 2r), with base area and radius shown.

Calculate the volume, base area, lateral surface area and total surface area of a cylinder from its radius and height.

Calculate the volume of a cylinder in litres, cm³ and m³ from its radius and height. Supports cm, mm, m, inches and feet.

Convert a cylinder's volume to US liquid gallons from dimensions in inches or centimetres — tanks, pools, pipes and drums.

Convert between cylindrical coordinates (ρ, θ, z) and Cartesian (x, y, z) in both directions. Instant results with angle in degrees.

Calculate the area, perimeter, circumradius, inradius and longest diagonal of a regular decagon (10-sided polygon) from its side length.

Convert decimal degrees to degrees-minutes-seconds (DMS) and back for GPS coordinates, mapping and surveying.

Convert any decimal to a simplified fraction and mixed number instantly, showing the step-by-step method.

Convert any decimal number to a percentage instantly — multiply by 100 and see the result with a visual proportion bar.

Apply Descartes' rule of signs to count the possible numbers of positive and negative real roots of any polynomial.

Calculate the determinant of a 2×2 or 3×3 matrix with full step-by-step cofactor expansion and a geometric visualisation.

Find the diagonal of a rectangle from its length and width using the Pythagorean theorem, plus area and perimeter.

Find the eigenvalues, eigenvectors, and diagonal decomposition A = PDP⁻¹ of a 2×2 real matrix, with step-by-step working.

Find the base diameter of a cone from its radius, plus slant height, volume, and surface areas in one step.

Convert between diameter and radius of a circle and get circumference and area instantly — works in both directions.

Find the two numbers that multiply to the top and add to the bottom of the diamond puzzle — instantly solves any diamond problem.

Find the digital root of any whole number by repeatedly summing its digits until one digit remains.

Enter length and width to instantly get the area, perimeter, diagonal and aspect ratio of any rectangle.

Calculate the straight-line distance between two Cartesian points (x₁,y₁) and (x₂,y₂) using the distance formula.

Calculate the Euclidean (straight-line) and Manhattan distances between two points in 2D using the distance formula d = √(Δx² + Δy²).

Find the shortest (perpendicular) distance from a 3D point to a plane defined by ax + by + cz + d = 0.

Apply the distributive property to expand a(b+c) or use FOIL to expand (a+b)(c+d) with a step-by-step solution.

Divide two complex numbers (a+bi)÷(c+di) and get the real part, imaginary part and magnitude of the quotient.

Divide two fractions (a/b) ÷ (c/d) by multiplying by the reciprocal. Get the simplified fraction and decimal instantly.

Divide exponents with the same base using the quotient rule: a^m ÷ a^n = a^(m−n). See the step-by-step solution instantly.

Divide two square-root expressions (c₁√a) ÷ (c₂√b) using the quotient property. Get the rationalized form and step-by-step solution.

Test whether any integer is divisible by 2 through 11 instantly — with the shortcut rule shown for each divisor.

Find every divisor of any integer up to 100 million. See the count, sum of divisors σ(N), and whether the number is perfect, abundant, or deficient.

Find the area of a regular dodecagon from its side length, circumradius, or apothem. Includes perimeter and all key dimensions.

Calculate area, perimeter, interior angle, circumradius, apothem and diagonal of a regular dodecagon from its side length.

Calculate sin(2θ), cos(2θ) and tan(2θ) for any angle using the double-angle formulas. Accepts degrees or radians.

Apply the double-angle formulas step by step: evaluate sin(2θ), cos(2θ) and tan(2θ) with full working shown.

Evaluate all double-angle identities — sin(2θ), all three forms of cos(2θ), tan(2θ) — plus derived half-angle values at any angle.

Calculate how many periods it takes for a quantity to double at a given growth rate — exact formula and Rule of 72 compared.

Calculate e^x or b^x, see the Taylor series expansion term by term, the derivative, logarithm, and an interactive graph.

Decompose any positive fraction into a sum of distinct unit fractions (1/n) using the greedy algorithm, the method used in ancient Egyptian arithmetic.

Calculate the eigenvalues and eigenvectors of a 2×2 matrix, solve the characteristic polynomial, and visualise how the matrix transforms space.

Solve a system of two linear equations by elimination. Enter the six coefficients, get x and y with a step-by-step solution.

Calculate the area of an ellipse from its semi-major and semi-minor axes using the exact formula A = π × a × b.

Calculate the perimeter (circumference) of an ellipse from its semi-axes using Ramanujan's highly accurate approximation formula.

Enter center and semi-axes of an ellipse to get its standard equation, foci, eccentricity, area and a plot — all in one step.

Find the missing endpoint of a line segment given its midpoint and the other endpoint — instant coordinate geometry.

Convert any number to engineering notation — powers of 10 in multiples of 3, with matching SI prefix (k, M, G, m, μ, n, p…).

Find the standard-form equation of a circle given the two endpoints of its diameter — calculates center, radius, area and circumference.

Calculate the area of an equilateral triangle from its side length or height — includes perimeter and derived dimensions.

Calculate the area, perimeter, height, inradius and circumradius of an equilateral triangle from its side length.

Find equivalent fractions by simplifying to lowest terms and scaling by any factor — shows a fraction bar and a table of common equivalents.

Find equivalent ratios by simplifying a:b to its lowest terms and scaling by any integer — shows a ratio bar and a table of common equivalents.

Calculate the Gaussian error function erf(x), complementary error function erfc(x), and scaled erfc for any real x.

Find the GCD of two integers using the Euclidean algorithm — see every division step, from start to remainder zero.

Calculate the straight-line (Euclidean) distance between two points in 2D or 3D space using the Pythagorean theorem.

Verify or complete Euler's polyhedron formula V − E + F = 2. Enter any two of vertices, edges and faces to find the third.

Get the exact radical form (e.g. √3/2) and decimal value of sin, cos, tan, csc, sec and cot for all standard angles 0°–360°.

Write any number in expanded form: break it into place-value addends (4523 = 4×1000 + 5×100 + 2×10 + 3) with powers of 10.

Expand logarithmic expressions using the product, quotient, and power rules. Shows the expanded symbolic form and computes the numeric result.

Convert any number to scientific notation (exponential form) and find its mantissa, exponent, log₁₀, and natural logarithm.

Evaluate f(x) = a × bˣ, determine growth or decay type, find the doubling time or half-life, and plot the exponential curve.

Calculate the final value, total growth and doubling time for discrete or continuous exponential growth.

Convert any number to scientific notation, engineering notation and E notation with a chosen number of significant figures.

Calculate all three exterior angles of a triangle from two interior angles and verify the exterior angle theorem.

Factor a quadratic trinomial ax² + bx + c into a(x − r₁)(x − r₂) using the quadratic formula, with step-by-step working and a parabola graph.

Compute a^(p−1) mod p to verify Fermat's little theorem, test primality and find the modular inverse a⁻¹ (mod p).

Calculate the fifth root of any real number instantly. Works for negative inputs, with a curve showing y = ⁵√x.

Calculate floor division ⌊a ÷ b⌋ and the true modulo remainder. Handles negative numbers correctly by rounding toward −∞, not toward zero.

Calculate the floor ⌊x⌋, ceiling ⌈x⌉, round, truncate and fractional part of any real number, with a number-line visualisation.

Find the foci, eccentricity, area and perimeter of an ellipse from its semi-major axis a and semi-minor axis b.

Calculate the fourth root of any non-negative number — the value that, raised to the power 4, equals x.

Convert any fraction to its decimal and percentage equivalents, simplify the fraction, and show the mixed-number form.

Convert any fraction to a percentage instantly. Enter the numerator and denominator to get the exact percentage, decimal equivalent and a visual bar.

Evaluate x^(p/q): raise any number to a fractional power and see the equivalent radical form plotted.

Multiply the number of choices for each independent event to find the total possible outcomes — up to 6 events.

Explore Galileo's paradox: count natural numbers vs perfect squares in [1, N] and see why infinite sets defy 'more' and 'fewer'.

Evaluate the Gamma function Γ(z) for any positive real number using the Lanczos approximation — accurate to ~15 significant digits.

Solve a 2×2 system of linear equations step by step using Gauss–Jordan elimination with full row-operation working.

Find the Greatest Common Factor (GCF) and Least Common Multiple (LCM) of two numbers using the Euclidean algorithm, with step-by-step working.

Convert a circle's centre (h, k) and radius r to its general form x² + y² + Dx + Ey + F = 0.

Convert a circle from general form x² + y² + Dx + Ey + F = 0 to standard form (x−h)² + (y−k)² = r² by completing the square.

Calculate the geometric mean of any list of positive numbers — the n-th root of their product. Useful for growth rates, ratios and log-scale data.

Calculate both sides, area, perimeter and diagonal of a golden rectangle from one side, using the golden ratio φ ≈ 1.6180.

Apply the Gram-Schmidt process to two 2-D vectors and compute the orthonormal basis e₁, e₂ step by step.

Solve and graph a linear inequality ax + b > c on a number line — shows boundary, interval notation, and open/closed endpoint.

Solve and graph ax² + bx + c > 0 (or ≥, <, ≤) — shows roots, vertex, solution set, and parabola graph.

Calculate the shortest distance between two points on Earth using the haversine formula: result in km, miles and nautical miles, plus the initial bearing.

Compare any two numbers and find whether A > B, A < B or A = B, plus the difference, ratio and percentage change between them.

Find the GCD of two denominators and the least common denominator (LCD) needed to add or subtract two fractions, with the simplified result.

Find the greatest common divisor (GCD) of two integers using the Euclidean algorithm, with full step-by-step working and the LCM as a bonus result.

Find the Greatest Common Factor (GCF) of two or more integers and list all their common factors, with Euclidean algorithm steps.

Compute the Hadamard (element-wise) product of two 2×2 matrices — multiply matching entries and see the step-by-step working.

Compute sin(θ/2), cos(θ/2) and tan(θ/2) from any angle in degrees or radians using the half-angle identities.

Calculate the harmonic mean of a list of non-zero numbers — the correct average for rates, speeds, and prices per unit.

Compute the nth harmonic number H(n) = 1 + 1/2 + 1/3 + … + 1/n, its asymptotic approximation, and the Euler–Mascheroni constant.

Find the perpendicular height of a cone from its radius and slant height (h = √(l²−r²)), or from its radius and volume (h = 3V/πr²).

Find the height of a cylinder from its radius and volume (h = V/πr²) or from its radius and lateral surface area (h = A/2πr).

Find the perpendicular height of a square pyramid from its base side and slant height (h = √(l²−(a/2)²)), or from its base side and volume.

Calculate the curved surface area (CSA = 2πr²) and total surface area (TSA = 3πr²) of a hemisphere from its radius.

Calculate the area of a regular heptagon from its side length, circumradius or apothem, with all derived dimensions.

Calculate the area, perimeter, apothem, circumradius, interior angles and diagonals of a regular heptagon from its side length.

Calculate the volume, total surface area, lateral area and slant height of a regular hexagonal pyramid from base side and height.

Find the total and lateral surface area of a regular hexagonal pyramid — enter base side and height, or base side and slant height.

Explore Hilbert's Hotel paradox: see how infinitely many rooms can always accommodate more guests by shifting room assignments.

Calculate the volume and surface area of a hollow cylinder (pipe or tube) from outer radius, inner radius and height.

Calculate all six hyperbolic functions (sinh, cosh, tanh, coth, sech, csch) and their inverses for any x.

Calculate the hypotenuse or a missing leg of a right triangle using a² + b² = c². Also computes angles, area, and perimeter.

Calculate powers of i (i^n = 1, i, −1, −i cycle), raise any complex number z = a+bi to the nth power, and find modulus, argument and conjugate.

Add, subtract, multiply or divide two complex numbers (a + bi) and find the result, modulus, argument and conjugate.

Convert any improper fraction (numerator ≥ denominator) to a simplified mixed number in one step, with the full working shown.

Convert any linear inequality (x > a, x ≤ a, a < x ≤ b …) to interval notation instantly, with a number-line diagram.

Calculate the inscribed angle from the central angle (arc) or vice versa. Applies the Inscribed Angle Theorem: inscribed angle = ½ × central angle.

Compute the GCD, LCM, quotient, remainder and basic arithmetic of any two integers instantly.

Find the exact (x, y) intersection point of two lines given in slope-intercept form y = mx + b, with a live graph.

Convert any inequality or set of real numbers to interval notation — with bracket type, set-builder form, and a number-line diagram.

Find the angle whose cosine equals a given value. Returns arccos(x) in degrees, radians or gradians for any x in [−1, 1].

Find the angle from a cosine value or from adjacent and hypotenuse sides of a right triangle. Outputs degrees, radians, and gradians.

Find the angle whose sine equals a given value. Returns arcsin(x) in degrees, radians or gradians for any x in [−1, 1].

Calculate arctan(x) or the quadrant-aware angle atan2(y, x) from coordinates — output in degrees and radians.

Calculate arcsin, arccos, arctan, arccsc, arcsec, or arccot of any valid input — angle in degrees and radians.

Calculate the gear involute function inv(α) = tan(α) − α and related gear parameters: base circle radius, module, addendum and dedendum.

Find the area and perimeter of any irregular polygon from its vertex coordinates using the Shoelace formula.

Calculate the area, perimeter, leg lengths and base angles of an irregular (general) trapezoid with two parallel sides and unequal legs.

Test whether (a mod b) mod c equals a mod (b mod c) for any three integers — and learn why modulo is not generally associative.

Calculate the area, height, perimeter, diagonal, and angles of an isosceles trapezoid from its two bases and equal leg.

Calculate the area, height, perimeter, diagonal and base angles of an isosceles trapezoid from its two parallel sides and leg length.

Find the equal leg (a) of an isosceles triangle from the base and one other known value: height, area, or base angle.

Calculate all three angles of an isosceles triangle from its sides, or find sides from the apex angle and base.

Calculate the area of an isosceles triangle from its equal side and base, or from the base and height directly.

Calculate the area, height, perimeter, angles, and medians of an isosceles triangle from its equal side and base.

Find the height (altitude) of an isosceles triangle from its equal side and base, from area and base, or from the equal side and apex angle.

Calculate the height, area, perimeter and angles of an isosceles triangle from its two equal legs and base.

Calculate the area and perimeter of a kite (quadrilateral) from its two diagonals. Formula: Area = (p × q) ÷ 2.

Calculate the Lagrange remainder bound for a Taylor polynomial: |Rₙ(x)| ≤ M · |x−a|^(n+1) / (n+1)!

Calculate the lateral (curved) surface area of a cone from radius and height or slant height: A = π·r·l, plus total surface area and volume.

Calculate the lateral surface area of a trapezoidal prism from the four sides of the trapezoid and the prism height.

Calculate the lateral (curved) surface area of a cylinder from radius and height, with total surface area and volume.

Calculate the latus rectum and semi-latus rectum of a parabola, ellipse or hyperbola from its defining parameters.

Find the Least Common Denominator (LCD) of two or three fractions, convert them to equivalent fractions and compute their sum.

Find the least (smallest) factor greater than 1 that two integers share — the smallest prime factor of their GCF.

Find the Least Common Multiple (LCM) of up to four integers using the GCD method, with full step-by-step working shown.

Find the least-squares regression line (y = mx + b), correlation coefficient r, and R² for any set of x,y data points.

Find the width of a rectangle when the perimeter and length are known. Also computes area, half-perimeter, and diagonal.

Calculate the distance between two coordinate points using the distance formula d = √((x₂−x₁)²+(y₂−y₁)²).

Find the length of a rectangle from its width and either its area (l = A ÷ w) or its perimeter (l = P/2 − w).

Find the parametric equation of the line where two planes intersect — direction vector via cross product and a point on the line.

Generate the output bit sequence of a Fibonacci LFSR with a maximal-length polynomial — choose stages (2–8), initial state, and steps.

Check whether three vectors in ℝ³ are linearly independent by computing the 3×3 determinant of the matrix they form.

Find an unknown y that lies on the straight line between two known (x, y) data points — the standard lerp formula.

Calculate the base-2 logarithm of any positive number, with log₁₀ and natural log shown alongside a plotted curve.

Add two whole numbers using the long addition method, with a full column-by-column breakdown showing every carry.

Divide two whole numbers using the long division method, with a step-by-step breakdown showing each digit, subtraction and remainder.

Multiply two whole numbers using the long multiplication method, showing each partial product and the final addition step by step.

Subtract two whole numbers using the long subtraction method, with a full column-by-column breakdown showing every borrow.

Find the lowest common denominator (LCD) of 2–4 fractions instantly, with step-by-step GCD/LCM working and a visual number line.

Reduce any fraction to its lowest terms (simplest form) instantly using the Euclidean algorithm, with a full step-by-step GCD derivation.

Decompose a 3×3 matrix into lower (L) and upper (U) triangular factors using Doolittle elimination, with step-by-step working and determinant.

Calculate the magic constant of an n×n magic square and display the actual grid for odd-order and doubly-even-order squares.

Calculate the Manhattan (taxicab/city-block) distance between two 2D points: |x₂ − x₁| + |y₂ − y₁|.

Calculate b raised to any power n — positive, negative, zero or fractional — with step-by-step working and a plotted power curve.

Multiply a 2×2 matrix by a scalar — every element is scaled by k — with the resulting matrix, determinant, and a geometric view of the transformation.

Calculate the Frobenius, 1-norm, ∞-norm and max-norm of a 2×2 matrix with step-by-step working and a comparison of all four norms.

Convert any whole number to Mayan numerals — dots (1), bars (5), shell (0) — with a step-by-step base-20 decomposition and glyph display.

Calculate all three midsegments of a triangle from its side lengths, plus the medial triangle area and perimeter.

Convert degrees, arc minutes and arc seconds (DMS) to decimal degrees — the format used in GPS, mapping, navigation and astronomy.

Calculate how often a "miraculous" rare event is statistically expected using Littlewood's Law — enter the probability and daily event rate.

Add, subtract, multiply or divide two mixed numbers — with full step-by-step working, simplification, and decimal result.

Convert any mixed number to an improper fraction instantly — with step-by-step working and simplification using GCD.

Calculate the surface area and edge length of a Möbius strip given its radius and strip width, with a 2-D boundary curve diagram.

Find the modular multiplicative inverse of a modulo m using the extended Euclidean algorithm. Returns x where (a × x) mod m = 1.

See how modulo behaves with negative dividends or divisors across the three conventions: truncated (JS/C), floored (Python), and Euclidean.

Explore how modulo (%) fits into PEMDAS/BODMAS precedence — same level as × and ÷ — with live worked examples and step-by-step evaluation.

Compute the Moore-Penrose pseudoinverse A† of any 2×2 matrix — handles full-rank, rank-1 and zero-matrix cases with verification.

Multiply any two numbers and see the product instantly. Works with decimals, negatives and large numbers.

Find the multiplicative inverse (reciprocal) of any non-zero number. 1/x — the number that when multiplied by x gives 1.

Find the multiplicative inverse of a number mod m — the x where a · x ≡ 1 (mod m), via the extended Euclidean algorithm.

Multiply two complex numbers (a + bi)(c + di) using FOIL — get the product, magnitude, and argument with an Argand-plane diagram.

Multiply two binomials (ax + b)(cx + d) using the FOIL method and get the expanded trinomial with step-by-step working.

Apply the product rule (xᵐ · xⁿ = x^(m+n)) or power rule ((xᵐ)ⁿ = x^(m·n)) to simplify and evaluate expressions with exponents.

Multiply two fractions (a/b × c/d) and instantly get the simplified result, decimal, and a step-by-step breakdown.

Multiply any two polynomials by entering comma-separated coefficients — get the expanded product and a step-by-step distributive breakdown.

Multiply radical expressions c₁·ⁿ√a × c₂·ⁿ√b and simplify: extracts the largest perfect nth-power factor to give the fully simplified form.

Calculate ln(x), log base 10, log base 2, eˣ, and the derivative 1/x for any positive number — with an animated ln curve.

Calculate the negative logarithm −log_b(x) in base 10, e, or 2. Used for pH, pKa, pOH, decibels, and information-theoretic measures.

Find the null space (kernel) of a 2×2 matrix: compute its determinant, rank, nullity and a basis for the null space.

Solve any oblique (non-right) triangle from SSS, SAS, AAS or SSA inputs — find all sides, angles, area, perimeter, inradius and circumradius.

Solve an obtuse triangle (one angle > 90°) — find all sides, angles, area, altitudes, inradius and circumradius from SSS or SAS inputs.

Calculate area, perimeter, circumradius, inradius, and all three diagonal lengths of a regular octagon from any known measurement.

Find the order of magnitude of any number: the integer exponent n so that |x| ≈ 10ⁿ. Also shows scientific notation and nearest powers of 10.

Find the orthocenter of any triangle given its three vertices. Shows coordinates, type (acute/right/obtuse), area and a plotted diagram.

Calculate the vertex, focus, directrix, axis of symmetry, x-intercepts and y-intercept of any parabola y = ax² + bx + c, with a live graph.

Calculate the area of a parallelogram from its base and perpendicular height. Optionally enter the side to get the perimeter too.

Calculate the perimeter of a parallelogram from its base and side length using the formula P = 2(a + b).

Multiply two whole numbers using the old partial-products method — breaks each factor into place values and shows every multiplication step.

Calculate the area, perimeter, circumradius, inradius, and diagonals of a regular pentagon from side length, circumradius, or apothem.

Calculate what percentage of a time period has elapsed and how much time remains, using any consistent time unit.

Calculate what percentage of a goal you have achieved, how much remains, and what percent is left — for any numeric target.

Calculate the percentage change between two values — finds the % increase or decrease from an original value to a new value.

Calculate the value after a percentage decrease, or find what % one value fell from another — simple formula, instant result.

Calculate the percentage difference between two values — symmetric formula using the average as the reference, not one specific starting point.

Calculate the value after a percentage increase, or find what % one value rose from another — quick formula, instant result.

Calculate the percentage point (pp) difference between two percentages and the relative % change — understand the key distinction between the two.

Check whether any integer is a perfect cube, find its exact integer cube root, and identify the nearest perfect cubes if it is not.

Check whether any non-negative integer is a perfect square, find its exact integer square root, and see the nearest perfect squares if it is not.

Expand a perfect square trinomial (a + b)² or (a − b)² into a² ± 2ab + b² with step-by-step working.

Calculate the perimeter of a circle, square, rectangle, triangle or regular polygon by entering the shape dimensions.

Find the perimeter of any quadrilateral by entering all four side lengths — works for rectangles, parallelograms, rhombuses, and irregular shapes.

Find the perimeter of a rectangle when you know its area and one side — the calculator derives the other side and computes 2(l + w).

Calculate the perimeter of a circular sector from the radius and central angle in degrees or radians — perimeter = 2r + arc length.

Find the perimeter and area of a triangle from its three vertex coordinates using the distance formula.

Add fractional or mixed-number side lengths of a triangle to find the perimeter — supports entries like 3/4, 1 2/3, or 0.75.

Calculate the perimeter of a rectangle from its length and width, plus area, diagonal, and aspect ratio.

Find the equation of a line perpendicular to a given line through a specific point, plus the foot of the perpendicular and the shortest distance.

Break any whole number into its place-value positions: ones, tens, hundreds, thousands and beyond.

Decompose a 2×2 matrix into an orthogonal factor Q (rotation/reflection) and a symmetric positive semidefinite factor S (stretch). Exact closed-form result.

Convert a complex number a + bi to polar form r∠θ and Euler form r·e^(iθ). Find the modulus and argument in degrees and radians.

Convert polar coordinates (r, θ) to Cartesian (x, y). Enter radius and angle in degrees or radians to get the rectangular point instantly.

Evaluate expressions written in Polish (prefix) notation. Operators come before their operands — no parentheses needed. Supports +, -, *, /, ^.

Calculate the interior angle, exterior angle, and angle sum of any regular polygon. Enter the number of sides to get all angle properties instantly.

Divide one polynomial by another using long division. Enter coefficients in descending degree order and get quotient, remainder, and full working steps.

Graph polynomial functions up to degree 4, evaluate f(x), find real roots, and identify the vertex of a parabola.

Evaluate the power function y = a·xⁿ for any real coefficient, exponent and x value, with a plotted curve.

Calculate (base^exponent) mod m — the remainder of a power divided by a modulus — using fast binary exponentiation.

Calculate 10 raised to any power (10ⁿ) and see the result in standard and scientific notation.

Calculate 2 raised to any power (2ⁿ) — instantly see memory sizes, bit depths and binary capacity values.

Apply power-reducing identities to express sin²(θ), cos²(θ) and tan²(θ) in terms of cos(2θ) — enter any angle.

Calculate any integer power of the imaginary unit i. i cycles through 1, i, −1, −i with period 4 — enter any exponent to get the result instantly.

Enter the four payoff values of a prisoner's dilemma game to find the Nash equilibrium, Pareto-optimal outcome, and social cost of defection.

Calculate all key angles of a right square pyramid: face inclination, lateral edge angle, apex angle, and the dihedral angle between adjacent faces.

Calculate the volume, base area, lateral surface area, and total surface area of a square, rectangular, or equilateral-triangle-base pyramid.

Solve any right triangle with the Pythagorean theorem. Enter any two sides to find the third, plus all angles, area, perimeter, and altitude to the hypotenuse.

Generate Pythagorean triples (a, b, c) with a² + b² = c² using Euclid's parametric formula for integers m > n ≥ 1.

Factor a 2×2 matrix A into an orthogonal matrix Q and upper-triangular matrix R using Gram-Schmidt orthogonalisation.

Solve any quadratic equation ax² + bx + c = 0. Get both roots (real or complex), the discriminant, vertex, and a parabola plot.

Calculate the area of four common quadrilaterals: rectangle, parallelogram, trapezoid, and rhombus using exact formulas.

Calculate area, perimeter and diagonals for rectangles, parallelograms, isosceles trapezoids and rhombuses — select shape and enter dimensions.

Calculate the area of a quarter circle from its radius, or find the radius from a known area. Formula: A = πr²/4.

Calculate the area, arc length, perimeter and centroid of a quarter circle from its radius.

Calculate the perimeter of a quarter circle: two radii plus the curved arc. Formula: P = 2r + πr/2.

Add, subtract or multiply two quaternions and compute the magnitude, conjugate and inverse. Shows step-by-step Hamilton product.

Calculate M/M/c queue metrics: utilisation, average queue length, waiting time and service probability using the Erlang-C formula.

Calculate the integer quotient and remainder of any division — shows truncated, floored and exact decimal results.

Calculate the nth root (square root, cube root, or any radical) of a number — with step-by-step result.

Find the radius of a circle from its area, circumference, or diameter using simple inverse circle formulas.

Find the base radius of a right circular cone from its volume, lateral surface area, or total surface area — given the height.

Find the base radius of a right circular cylinder from its volume, lateral surface area, or total surface area — given the height.

Find the radius of a sphere from its volume or surface area, or compute volume, surface area and diameter from radius.

Simplify the ratio of three numbers to lowest terms and show each number as a percentage of the combined total A + B + C.

Find the simplified ratio of two numbers A : B, convert to a unit ratio, and see each number as a percentage of the combined total.

Evaluate x raised to a fractional exponent p/q, with step-by-step root-then-power working and a curve showing where your value falls.

Find all possible rational zeros of a polynomial using the Rational Root Theorem: ±(factors of constant term) ÷ (factors of leading coefficient).

Rationalize the denominator of a/√b by multiplying by √b/√b, automatically simplifying perfect-square factors and reducing the resulting fraction.

Find the point that divides a line segment AB in a given ratio m:n — internally or externally — using the section formula.

Find the reciprocal (multiplicative inverse) of any non-zero number: 1 ÷ x. Decimals, fractions and negatives all supported.

Calculate the area, perimeter, diagonal and aspect ratio of a rectangle from its length and width in any unit.

Calculate the diagonal length and its angle in a rectangle from width and height. Uses the Pythagorean theorem and trigonometry.

Solve a rectangle from any two known values — length, width, area, or perimeter — and get all four measurements plus the diagonal.

Scale a rectangle by any factor: find new width, height, area, perimeter and diagonal. Area scales as k², linear dimensions scale as k.

Calculate the volume, surface area, space diagonal and face diagonals of a rectangular prism (cuboid) from its length, width and height.

Calculate the volume, total surface area, lateral surface area, space diagonal and base perimeter of a rectangular prism from length, width and height.

Calculate the volume, base area, lateral and total surface areas, slant heights and apex edge of a rectangular pyramid from its base dimensions and height.

Calculate area, perimeter, apothem, long and short diagonals of a regular hexagon from side length, apothem, perimeter or area.

Calculate the relative change (dimensionless ratio) and percent change between a reference value and a new value.

Check whether two integers are relatively prime (coprime) — GCD = 1 — using the Euclidean algorithm with every step shown.

Find the quotient and remainder of integer division. Shows the full a = b × q + r breakdown step by step, including the modulo.

Factor any quadratic ax² + bx + c into (px + q)(rx + s) using the AC / grouping method with step-by-step working.

Calculate the area and perimeter of a rhombus using diagonals, base and height, or side length and interior angle — three input methods.

Calculate the volume, total surface area, lateral surface area and slant height of a right circular cone from radius and height.

Calculate the volume, total and lateral surface area, base area and space diagonal of a right circular cylinder from radius and height.

Calculate volume, total surface area, lateral surface area, slant heights and lateral edge of a right rectangular pyramid from base length, width and height.

Calculate volume, total surface area, lateral surface area, slant height and lateral edge of a right square pyramid from base side and height.

Calculate the area of a right trapezoid from its two parallel bases and perpendicular height, with a step-by-step formula walkthrough.

Calculate area, perimeter, slant side, diagonals and angles of a right trapezoid from its two parallel bases and perpendicular height.

Calculate slope (rise ÷ run), angle in degrees and percent grade from rise/run values or two coordinate points.

Calculate the root mean square (RMS) of any set of numbers. Works with positive and negative values; shows sum of squares and arithmetic mean.

Rotate any 2D point (x, y) by any angle about the origin using the rotation matrix formula. Shows new coordinates, distance, and angles.

Round any dollar amount to the nearest cent ($0.01) — shows the rounded result, ceiling (always up), floor (always down) and the rounding difference.

Round any dollar amount to the nearest whole dollar — shows the rounded result, ceiling (always up), floor (always down) and the rounding difference.

Instantly round any number to the nearest 100. See the lower and upper hundreds and the rounding error.

Round any number to 2 decimal places (nearest 0.01). See the bounding hundredths and the exact rounding error.

Round any decimal to the nearest whole number. See floor, ceiling and rounding error instantly on a number line.

Round any monetary amount to the nearest cent or penny (2 decimal places). Essential for retail and financial calculations.

Round any number to the nearest multiple of 10. See the tens above and below and the rounding error instantly.

Round any number to 1 decimal place (nearest 0.1). See the tenths above and below and the exact rounding error.

Round any number to the nearest 1,000 instantly, with lower and upper bounding thousands and the rounding distance.

Round any number to three decimal places (nearest 0.001) with lower and upper bounding thousandths and the rounding error.

Convert any matrix to row echelon form (REF) step by step using Gaussian elimination with partial pivoting — up to 6 × 7.

Given two sides and the included angle (SAS), find the third side, all angles, area and perimeter using the Law of Cosines.

Calculate the area, perimeter, heights and angles of a scalene triangle from its three side lengths using Heron's formula.

Calculate the area, perimeter, all three angles, inradius and circumradius of any triangle from its three side lengths.

Plot (x, y) data pairs on a scatter chart, compute Pearson correlation r, R², and fit a least-squares regression line.

Apply the segment addition postulate AB + BC = AC to find any missing segment length instantly.

Calculate the area of a circular segment from the radius and central angle, plus arc length, chord, and sagitta.

Calculate the area, perimeter, arc length, and diameter of a semicircle given its radius.

Calculate the nth term and sum of an arithmetic or geometric sequence. Enter the first term, common difference or ratio, and n.

Enter two sets of numbers to compute their union, intersection, difference and symmetric difference — with a visual number line.

Count the significant figures in any number and round it to a specified number of sig figs, with a step-by-step explanation of the rules.

Find missing sides of similar triangles. Enter all three sides of the reference triangle and one corresponding side to get the scale factor and remaining sides.

Simplify ∛N by extracting the largest perfect-cube factor and expressing the result as k∛m in simplest radical form.

Reduce any fraction to its lowest terms in one step using the GCD — shows the simplified form, decimal value, and a visual fraction bar.

Simplify √N by extracting the largest perfect-square factor and writing the result as k√m in simplest radical form.

Reduce a ratio A:B (or A:B:C) to its simplest whole-number form by dividing all parts by their GCD.

Find the sine of any angle entered in degrees. Also shows cosine, tangent and the equivalent angle in radians.

Solve a triangle using the Law of Sines: enter two angles and one side to find all remaining sides, angles, perimeter and area.

Calculate sin, cos, tan, cot, sec and csc for any angle in degrees or radians — all six trigonometric ratios at once.

Calculate sin(2θ) using the double-angle identity 2 sin θ cos θ, plus cos(2θ) and tan(2θ), for any angle in degrees or radians.

Compute sin(θ) for any angle θ in degrees or radians, with the unit-circle coordinates, cos, tan and csc shown alongside.

Calculate sin⁻¹(x) — the angle whose sine equals x — in degrees and radians, for any x in [−1, 1].

Explore y = A·sin(Bx + C) + D: compute amplitude, period, frequency, phase shift and the function value at any x.

Compute the singular values σ₁ ≥ σ₂ of a 2×2 real matrix, plus condition number, nuclear norm and Frobenius norm.

Calculate the slant height of a square pyramid from perpendicular height and base side — plus lateral area, total area and volume.

Calculate the slant height of a cone from height and base radius — plus lateral area, total surface area, volume and apex half-angle.

Convert between slope percentage, angle (degrees), rise-over-run ratio and decimal slope in any direction. Useful for roads, ramps and roof pitches.

Find the slope-intercept equation y = mx + b from two points, a point and slope, or m and b directly. Evaluate y at any x and plot the line.

Find all sides of a similar triangle using the scale factor — enter the three sides of the original and one known side of the similar triangle.

Find the standard and general equation of a sphere in 3D from center coordinates and radius, plus volume and surface area.

Calculate the surface area of a sphere from its radius using 4πr². Also shows diameter, great-circle area and circumference.

Calculate the volume, surface area, diameter and circumference of a sphere from its radius or diameter with step-by-step working.

Convert between Cartesian (x, y, z) and spherical (r, θ, φ) coordinates in both directions, with radians and degrees.

Calculate the exact arc length of an Archimedean spiral from inner radius, outer radius, and number of turns.

Calculate the area, perimeter and diagonal of a square from its side length. Supports mm, cm, m, km, in, ft, yd and mi.

Calculate the diagonal of a square from its side length using d = s√2, plus area and perimeter.

Calculate the area of a rectangle in square feet from length and width in any unit — feet, inches, yards or metres.

Calculate the area of a circle in square inches from its diameter. Also converts to square feet and square centimetres.

Find the side, area and perimeter of the largest square fitting inside a circle, given the radius — or vice versa.

Expand (a + b)² using the binomial square identity a² + 2ab + b² — with step-by-step working.

Calculate the perimeter of a square from its side length using P = 4s, plus area and diagonal.

Calculate the volume, total surface area, lateral area, slant height, and lateral edge of a right square pyramid.

Calculate the volume of a square pyramid from its base side and height using V = ⅓a²h, with step-by-step working.

Calculate the square root of any non-negative number, plus reciprocal, cube root, and a visual y = √x curve.

Solve a triangle from two sides and a non-included angle (SSA) — handles the ambiguous case where 0, 1, or 2 triangles exist.

Solve a triangle from all three side lengths (SSS) — find all angles, area, perimeter, inradius, circumradius and altitudes.

Write the standard (centre-radius) equation (x−h)²+(y−k)²=r² for any circle and find its area, circumference and axis intercepts.

Convert any number to standard form (scientific notation) a × 10ⁿ instantly, with the mantissa, exponent and step-by-step working.

Convert a linear equation from standard form Ax + By = C to slope-intercept form y = mx + b, with step-by-step working and a line plot.

Convert a number from scientific notation (a × 10ⁿ) to standard (decimal) notation with step-by-step decimal-place shifting.

Convert a circle equation between standard form (x−h)²+(y−k)²=r² and general form x²+y²+Dx+Ey+F=0 in both directions.

Calculate the area, perimeter, side length, and tip angle of a regular n-pointed star polygon given its outer and inner radii.

Solve the rope-around-the-Earth puzzle: how high does a rope rise when extra length is added to a loop around any sphere? Answer: Δr = ΔC ÷ 2π.

Solve a 2-variable linear system by substitution — enter the six coefficients and get x, y, a graph of the intersection, and every working step.

Subtract two fractions with different denominators — finds the LCD, converts both fractions, subtracts, and simplifies to lowest terms with every step shown.

Subtract any two numbers (integers or decimals) and see minuend, subtrahend, and difference on an animated number line.

Calculate sin, cos, and tan of the sum (A+B) and difference (A−B) of two angles using the trigonometric sum and difference identities.

Calculate the sum of an arithmetic (linear) sequence given the first term, common difference and number of terms.

Find the partial sum of an arithmetic or geometric series; shows the infinite-sum limit for convergent geometric series with |r| < 1.

Calculate SUMPRODUCT = Σ(aᵢ × bᵢ): multiply matching elements of two arrays then sum all the products — identical to a vector dot product.

Find the supplementary angle (180° − θ) for any angle, plus the key trig identities sin(180°−θ) = sin θ and cos(180°−θ) = −cos θ.

Calculate the total and lateral surface area of a cylinder from radius and height — TSA = 2πr(r + h).

Calculate the area, perimeter and diagonal of a rectangle from its length and width using A = l × w.

Calculate the total surface area of a rectangular prism (cuboid) from length, width and height — TSA = 2(lw + lh + wh).

Calculate the total and lateral surface area of a rectangular pyramid from base length, base width and height.

Calculate the total surface area of a square pyramid from its base side length and height — TSA = b² + 2bs.

Calculate the total surface area and volume of a triangular prism from its three base sides and prism length.

Calculate the SA:V ratio for a sphere, cube, cylinder or cuboid — essential in biology, chemistry and engineering.

Find the angle of a right triangle from its opposite and adjacent sides using the inverse tangent — with sin, cos, hypotenuse and a triangle diagram.

Calculate tan⁻¹(x) — the inverse tangent of any real number — in degrees or radians, with the matching right-triangle diagram.

Calculate the tangent of any angle in degrees or radians, with sin, cos, cot, sec, and a live plot of y = tan(x).

Calculate the tangent ratio, missing side, or angle of a right triangle. Instantly find opposite, adjacent, hypotenuse, sin, and cos.

Find the tangent length from an external point to a circle, the tangent angle, power of a point, and triangle area using L = √(d² − r²).

Compute the tensor (outer) product of two 2-D vectors: returns the 2×2 result matrix with all entries, Frobenius norm, trace, and determinant.

Determine whether a fraction terminates or has a repeating decimal, and show the full decimal expansion with the repeating cycle in parentheses.

Calculate the volume, surface area, height, inradius and circumradius of a regular tetrahedron from its edge length.

Calculate the surface area and volume of a torus (donut shape) from its major and minor radii using the Pappus theorem formulas.

Calculate the volume and surface area of a torus (donut shape) from its major and minor radii using V = 2π²Rr².

Find all four interior angles of an isosceles trapezoid from the two parallel sides and the leg length.

Calculate the perpendicular height of a trapezoid from its area and parallel sides, or from the equal leg length of an isosceles trapezoid.

Find the midsegment of a trapezoid from its two bases, find a missing base from the midsegment, or calculate the area using the midsegment and height.

Calculate the perimeter of a trapezoid from its four sides: two parallel bases and two non-parallel legs.

Find a missing side of a trapezoid from the perimeter and three known sides, or from the area, height, and one base.

Calculate the volume and surface area of a trapezoidal prism from the two parallel bases, the trapezoid height, and the prism length.

Find all three angles of a triangle from three sides (SSS) or two sides and the included angle (SAS) using the law of cosines.

Find the third interior angle of a triangle and all three exterior angles — with triangle classification (acute, right, obtuse, scalene, isosceles, equilateral).

Calculate a triangle's area from base and height, two sides and an angle (SAS), or all three sides with Heron's formula.

Find the area of a triangle from its three vertex coordinates (x₁,y₁), (x₂,y₂), (x₃,y₃) using the shoelace formula.

Calculate the area of a triangle in square feet from its base and height in any unit — feet, inches, metres, or more.

Find the area of a triangle from two sides and the included angle (SAS) using A = ½ab·sin(C). Also derives the third side and all angles.

Solve a triangle from its three sides (SSS): find all angles via the law of cosines and the area, perimeter, inradius, and circumradius via Heron's formula.

Check if two triangles are congruent or similar. Enter three sides for each triangle and see which congruence criteria (SSS, SAS, ASA, AAS, HL) apply.

Find the missing interior angle of a triangle in degrees. Enter two known angles; the third is computed as 180° minus their sum.

Find all three altitudes (heights) of a triangle from its three side lengths using the area from Heron's formula.

Check whether three side lengths satisfy the triangle inequality and can form a valid triangle. Shows all three conditions.

Calculate the perimeter, area, all three angles, inradius, and circumradius of any triangle from its three side lengths.

Apply the Triangle Proportionality Theorem: if a line is parallel to one side of a triangle, find the missing segment using AD/DB = AE/EC.

Find the actual side lengths of a triangle whose sides are in a given ratio r₁:r₂:r₃, using the known perimeter.