Triangular Prism Calculator — Volume & Surface Area
Enter the two legs of the right-triangle cross-section and the prism length to compute volume, total surface area, lateral area and hypotenuse in one step.
units
units
units
V = ½ · a · b · L
- 1
Hypotenuse of base triangle
c = √(3² + 4²) = 5Pythagorean theorem on the two right-triangle legs. - 2
Base triangle area
½ × 3 × 4 = 6 - 3
Volume
base area × L = 6 × 10 = 60
How does this calculator work?
For a right triangular prism with legs a, b and length L: Volume = ½·a·b·L; Total surface area = a·b + (a+b+√(a²+b²))·L. The hypotenuse of the base is c = √(a²+b²). Enter the two legs and the prism length to get all key measurements instantly.
Formula
How this is calculated
A right triangular prism has two congruent right-triangle ends and three rectangular lateral faces. The right-triangle base has legs a and b; its area is ½ · a · b and its hypotenuse is c = √(a² + b²) from the Pythagorean theorem. The three rectangular faces have widths a, b and c respectively, each of length L (the prism depth), giving lateral area = (a + b + c) · L.
Total surface area = 2 · (base triangle area) + lateral area = a · b + (a + b + c) · L. Volume equals base area times length: V = ½ · a · b · L.
All inputs must share the same unit; outputs are in square and cubic units. If you have a non-right-triangle cross-section, you can use the surface-area-of-a-triangular-prism calculator which accepts any three side lengths via Heron's formula.
Frequently asked questions
This calculator assumes a right-triangle cross-section so it can compute the hypotenuse from the two legs using the Pythagorean theorem. For a general triangle cross-section (any three sides a, b, c) use the surface-area-of-a-triangular-prism calculator, which applies Heron's formula to the base.
Volume = base area × length. The base is a right triangle with area = ½ · a · b, so V = ½ · a · b · L. This is the same as an extruded cross-section: you are essentially sliding the triangular face a distance L through space.
All three inputs (legs a, b and prism length L) must be in the same unit. The surface area is then in square units and the volume is in cubic units. For example, if you enter centimetres the surface area is in cm² and the volume is in cm³.
Also known as
TG we-Calculate Editorial Team. (2026). Triangular Prism Calculator — Volume & Surface Area [Online calculator]. TG we-Calculate. https://we-calculate.com/calculator/triangular-prism-calculator
TG we-Calculate Editorial Team. "Triangular Prism Calculator — Volume & Surface Area." TG we-Calculate. 2026. https://we-calculate.com/calculator/triangular-prism-calculator.
TG we-Calculate Editorial Team, "Triangular Prism Calculator — Volume & Surface Area," TG we-Calculate, 2026. [Online]. Available: https://we-calculate.com/calculator/triangular-prism-calculator
@misc{wecalculate_triangular_prism_calculator, title = {Triangular Prism Calculator — Volume & Surface Area}, author = {{TG we-Calculate Editorial Team}}, howpublished = {\url{https://we-calculate.com/calculator/triangular-prism-calculator}}, year = {2026}, note = {TG we-Calculate} }
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