Prism Calculator

A prism has the same cross-section along its length. The most common is the cuboid (a box); a triangular prism has a triangle as its base.

Prism
Results update as you type.

Volume

240

Total surface area (TSA)
248
Lateral surface area (four walls)
128
Space diagonal
12.32882801

About this calculator

Choose the type and enter the sizes.

How to use it

  1. Choose cuboid or triangular prism.
  2. Enter the dimensions.
  3. Read the results.

The formula

Volume = base area × length; cuboid TSA = 2(lw + wh + hl)
base area
for a triangle, by Heron’s formula

Worked example

A 10 × 6 × 4 box

  1. Volume 240; TSA 248.
  2. Four walls 128; space diagonal ≈ 12.33.

What the result means

The four-walls area (LSA) is what you paint in a room, without floor and ceiling.

Assumptions

  • All lengths in the same unit.

Limitations

  • Results are rounded to 10 significant figures.

Frequently asked questions

What is the volume of a cuboid?

Length × width × height.

What is the TSA of a cuboid?

2(lw + wh + hl).

How do I find a triangular prism’s volume?

Triangle area × length.

Last reviewed on 3 October 2026. Found a mistake? Tell us.