Triangular Prism Volume
From the triangular end face and the length of the prism, get the cross-sectional area and the volume — the two numbers that describe any right triangular prism.
Three inputs, two answers
Enter the triangle base, the triangle height, and the prism length and the calculator returns the cross-section area (½ × base × height) and the volume (area × length) at once.
Keep units consistent
All three measurements are unit-agnostic — your answers come back in the same unit (squared for the area, cubed for the volume), so don't mix centimetres with inches.
What is a triangular prism volume calculator?
Triangle and length in, full prism out
A triangular prism is a solid with two identical triangular ends joined by three flat rectangular sides — think of a Toblerone bar, a tent, or a ridged roof. A triangular prism volume calculator turns three measurements — the base of the triangle, the height of the triangle, and the length of the prism — into the space the shape encloses. Because the cross-section is the same all along its length, the volume is simply the area of that triangle multiplied by how long the prism runs.
Enter the triangle base, triangle height, and prism length in any length unit to get the cross-section area and the volume instantly.
The volume of any prism is the area of its cross-section times its length. For a triangular prism the cross-section is a triangle, whose area is one-half of the base times the height.
volume = ½ × base × height × lengthThe first step finds the cross-sectional area — the size of the triangular end face — as ½ × base × height. Multiplying that area by the prism length (the distance between the two triangular ends) sweeps the triangle along the prism and gives the volume.
Suppose the triangular end has a base of 6 and a height of 4, and the prism is 10 long.
Cross-section area
½ × 6 × 4 = 12 square units — the area of the triangular end face.
Volume
12 × 10 = 120 cubic units — the area swept along the length of the prism.
The two outputs answer two different questions. The cross-section area (12 square units for a 6-by-4 triangle) is the size of the flat triangular end — useful if you are cutting the end pieces or working out how much the prism would cover end-on. The volume (120 cubic units here) is the space inside — the chocolate in a Toblerone, the air in a ridge tent, the concrete in a triangular curb. The key insight is that a prism has the same cross-section everywhere along its length, so doubling the length doubles the volume, while changing the triangle changes both the area and the volume together. If you only know the three side lengths of the triangle rather than a base and a height, find the triangle's area with Heron's formula first, then multiply by the length.
The formula is exact, but a couple of practical points are worth keeping in mind.
Right prisms and consistent units
This formula describes a right prism — one whose triangular ends sit square to the length, so the cross-section is constant. An oblique prism (sheared to one side) of the same length and triangle still has this volume, but a tapering or irregular shape does not. The base and height must be the perpendicular pair of the triangle (height measured at a right angle to the base), and all three inputs must share one unit: base, height, and length in centimetres give a volume in cubic centimetres, never a mix.