Triangular prism volume calculator
Enter the three sides of the triangle and the prism length; the tool finds the triangle area with Heron's formula, then the volume.
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How to use it
- Enter side a, side b, side c, prism length and length unit.
- The result appears straight away and updates as you edit.
- Copy the result, or copy a link that keeps the same values to share it.
How it is calculated
s = (a + b + c)/2, triangle area A = √(s(s−a)(s−b)(s−c)), volume = A × L, total area = 2A + (a + b + c) × L.
Example
Inputs: Side a = 3, Side b = 4, Side c = 5, Prism length = 10, Length unit = Centimeter (cm). Result: Volume: 60 cm³; Triangle base area: 6 cm²; Total surface area: 132 cm².
Limits and caveats
- Assumes a right prism whose side faces are rectangles perpendicular to the base.
- Results are in the cube or square of the unit you chose, so enter every dimension in that same unit.
Questions about this tool
What is the triangular prism volume formula?
Volume = triangle area × prism length. A 3-4-5 triangle has area 6, so with length 10 the volume is 60.
I only know the triangle base and height.
Then the triangle area is base × height / 2; multiply it by the length. This tool uses all three sides so it can also give the total surface area.
Why do I get a "not a triangle" message?
Any two sides must add up to more than the third. Sides 1, 2 and 5 cannot meet.