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
| Field | What to enter |
|---|---|
| Triangle side a | Units: m, cm, mm, km, in, ft … |
| Triangle side b | Units: m, cm, mm, km, in, ft … |
| Triangle side c | Units: m, cm, mm, km, in, ft … |
| Prism length | Units: 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) |
|---|---|
| 1.5 | 24.8 |
| 2.25 | 43.91 |
| 3 | 60 |
| 3.75 | 73.92 |
| 4.5 | 85.49 |
| 6 | 99.22 |
Formula
V = triangle area × lengthWorked 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.
Frequently asked questions
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.