Rate Law Calculator
Calculate the instantaneous rate of a chemical reaction from its rate law and determine the overall reaction order.
mol/L
mol/L
- 1
[A]^m term
1.5^1 = 1.5 - 2
[B]^n term
0.8^2 = 0.64 - 3
Overall reaction order
1 + 2 = 3Sum of partial orders m + n; determines units of k - 4
Reaction rate
0.05 × 1.5 × 0.64 = 0.048
How does this calculator work?
A rate law gives the reaction rate as rate = k[A]^m[B]^n. Multiply the rate constant by each concentration raised to its order; the overall order is m + n. Enter k, [A], [B], and the orders to get the instantaneous rate in mol/(L·s) and the overall order.
Formula
How this is calculated
The rate law expresses how the speed of a reaction depends on reactant concentrations. Enter the rate constant k, the molar concentrations [A] and [B] (in mol/L), and the partial orders m and n with respect to each reactant. The orders are usually small integers (0, 1, 2) determined experimentally, but they can be fractional.
The calculator raises each concentration to its order, multiplies the two terms by k, and reports the rate. The overall reaction order is simply m + n; this also fixes the units of k (for an overall order p, k has units of mol^(1−p)·L^(p−1)·s⁻¹). The result here is expressed in mol/(L·s), assuming k carries the matching units.
Concentrations must be non-negative. A concentration of zero with a positive order gives a rate of zero, while a zero order makes that term equal to one regardless of concentration. Negative or non-numeric inputs return no result.
Frequently asked questions
Reaction orders are determined experimentally, typically by the method of initial rates: vary one reactant concentration while holding others constant and observe how the rate changes. They cannot be read off the balanced equation.
The overall order is the sum of the individual orders, m + n. It describes the combined sensitivity of the rate to all reactant concentrations and determines the units of the rate constant k.
The units of k depend on the overall order p so that the rate comes out in mol/(L·s): k has units of mol^(1−p)·L^(p−1)·s⁻¹. For a second-order reaction, for example, k is in L/(mol·s).
Also known as
TG we-Calculate Editorial Team. (2026). Rate Law Calculator [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/rate-law-calculator
TG we-Calculate Editorial Team. "Rate Law Calculator." TG we-Calculate. 2026. https://we-calculate.com/calculator/rate-law-calculator.
TG we-Calculate Editorial Team, "Rate Law Calculator," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/rate-law-calculator
@misc{wecalculate_rate_law_calculator, title = {Rate Law Calculator}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/rate-law-calculator}}, year = {2026}, note = {TG we-Calculate} }
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