What is the formula for the volume of a triangular prism?

The volume is V = (1/2) · b · h · l, where b is the base of the triangular cross-section, h is the perpendicular height of the triangle, and l is the length of the prism. This equals the area of the triangular face multiplied by the prism length.

What is the difference between triangle height and prism length?

The triangle height (h) is the perpendicular distance from the base of the triangular face to the opposite vertex. The prism length (l) is how far the triangular shape is extruded — essentially the depth or thickness of the prism.

Does the triangle have to be a right triangle?

No. The formula V = (1/2) · b · h · l works for any triangle — right, acute, or obtuse — as long as h is the true perpendicular height from the base to the opposite vertex.

How many decimal places does the result use?

Results are shown to 4 decimal places. The internal calculation uses full floating-point precision, so you can rely on the displayed value for most practical purposes.

How is cross-sectional area related to volume?

The cross-sectional area is A = (1/2) · b · h (the area of the triangular face). The volume is simply that area multiplied by the prism length: V = A · l.

Volume of a Triangular Prism Calculator

Enter the base, triangle height, and prism length to instantly calculate its volume using V = (1/2) · b · h · l.

Prism Dimensions

Unit

Triangle Base (b)

Triangle Height (h)

Prism Length (l)

Formula Reference

Volume V = (1/2) · b · h · l

Cross-section Area A = (1/2) · b · h

Lateral Surface S = perimeter · l

Enter the base, triangle height, and prism length, then click Calculate Volume.

Triangular Prism Diagram

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Summary

This calculator computes the volume of a triangular prism using the formula V = (1/2) · b · h · l, where b is the base of the triangular cross-section, h is the height of that triangle, and l is the length (depth) of the prism. Results are displayed in cubic units matching your selected measurement system. Supplementary surface-area outputs assume the apex is centered above the base (an isosceles triangular cross-section).

How it works

Enter the base length of the triangular face.
Enter the perpendicular height of the triangular face.
Enter the length (depth) of the prism.
Select your preferred unit (cm, m, in, or ft).
The volume and cross-sectional area are calculated instantly.
Use the Copy button to copy the volume result to your clipboard.

Use cases

Calculate the volume of a wedge-shaped structural element.
Estimate fill material for triangular-profile trenches.
Solve geometry homework problems involving prisms.
Determine capacity of triangular-cross-section containers.
Compute material volume for roof ridge or ramp designs.
Verify 3D model dimensions during product design.
Calculate concrete needed for triangular footing forms.

Frequently Asked Questions

Last updated: 2026-05-25 · Reviewed by Nham Vu