Prism Calculator
Base area times length, for any cross-section.
Work out Prism. Base area times length, for any cross-section. Shows the working, not just the answer.
Optional, for surface area.
Volume
50
base 10 × length 5
A prism's volume is base area × length whatever the base shape — triangular, hexagonal, or an irregular outline. The cross-section is constant along the length, so the volume is just that cross-section dragged through space. Surface area is the two end faces plus the lateral surface, which unrolls flat into a rectangle of base-perimeter × length. The same reasoning gives a cylinder, which is simply a prism with a circular base.
How the Prism Calculator works
Enter the base area and the length for the volume, and add the base perimeter for the surface area. It works for any prism — triangular, hexagonal, or an irregular outline — because the cross-section is constant along the length.
Also known as: prism volume calculator · triangular prism volume calculator · prism surface area calculator · volume of a prism formula
Frequently asked questions
How do I find the volume of a prism?
Base area × length, whatever the base shape. The cross-section does not change along the length, so the volume is that cross-section dragged through space.
How do I find the surface area?
Two base faces plus the lateral surface, which unrolls flat into a rectangle of base-perimeter × length. That unrolling is why the perimeter is what is needed rather than the shape's details.
Is a cylinder a prism?
Informally yes — it follows exactly the same rule with a circular base, giving πr² × height. Strict definitions reserve prism for polygonal bases, but the arithmetic is identical.
What if the prism is slanted?
The volume is unchanged, provided the length used is the perpendicular height rather than the slanted edge. That is Cavalieri's principle: same cross-section and same height means same volume.
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