# Triangular Prism Calculator

URL: https://speedycalculator.com/calculators/math/triangular-prism/
Last updated: 2026-10-25

> The triangular prism calculator finds the volume and surface area of a prism with a triangular cross-section from the triangle’s three sides and the prism length.

## Inputs

- Triangle side a (m, cm, mm, km, in, ft, yd, mi)
- Triangle side b (m, cm, mm, km, in, ft, yd, mi)
- Triangle side c (m, cm, mm, km, in, ft, yd, mi)
- Prism length (m, cm, mm, km, in, ft, yd, mi)

## Results

- Triangle area
- Volume
- Surface area

## Formula

```
V = triangle area × length
```

## Explanation

Tents, roof sections and Toblerone boxes are triangular prisms.

### How to use the Triangular Prism Calculator

- **Triangle side a**
- **Triangle side b**
- **Triangle side c**
- **Prism length**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Heron’s formula gives the area of the triangular end; multiply by the length for volume.

### Inputs explained

FieldWhat to enterTriangle side aUnits: m, cm, mm, km, in, ft …Triangle side bUnits: m, cm, mm, km, in, ft …Triangle side cUnits: m, cm, mm, km, in, ft …Prism lengthUnits: m, cm, mm, km, in, ft …

### What each result means

- **Triangle area** = sqrt([Semi-perimeter]×([Semi-perimeter]-[Triangle side a])×([Semi-perimeter]-[Triangle side b])×([Semi-perimeter]-[Triangle side c]))
- **Volume** = [Triangle area]×[Prism length]
- **Surface area** = 2×[Triangle area] + ([Triangle side a] + [Triangle side b] + [Triangle side c])×[Prism length]

### Example values

How the main result changes when **Triangle side a** changes and everything else stays at the example values above:

Triangle side a (m)Volume (m³)1.524.82.2543.913603.7573.924.585.49699.22

## Worked example

Inputs — Triangle side a: 3 m; Triangle side b: 4 m; Triangle side c: 5 m; Prism length: 10 m.

Results — Triangle area = 6 m²; **Volume = 60 m³**; Surface area = 132 m².

## FAQ

**What if I know base and height instead?**
Triangle area = ½ × base × height; multiply by length.

**Do the sides need to form a triangle?**
Yes, each must be shorter than the sum of the other two.

**What formula does the Triangular Prism Calculator use?**
V = triangle area × length.