Prism Calculator
Base area times length, for any cross-section.
Base area times length, for any cross-section. Enter the base area and the length for the volume, and add the base perimeter for the surface area.
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
Where to go next
The Prism question rarely arrives on its own. These are the ones that usually come with it:
- Cylinder Calculator — Volume, surface area, and the label that peels off flat.
- Volume Calculator — Six shapes, with the litre conversion built in.
- Surface Area Calculator — Six shapes, and the ratio that explains why small things cool fast.
- Percentage Calculator — Every common percentage question in one place.
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.
Put this calculator on your own site
Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.
<iframe src="https://www.thecalclibrary.com/embed/prism-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Prism Calculator"></iframe>
<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/prism-calculator" style="color:#64748b">Prism Calculator</a> from The Calc Library</p>The only condition is that the credit line below the frame stays in place. That one line is what pays for the tool being free — it is how anyone else finds it.
Related calculators
Cylinder Calculator
Volume, surface area, and the label that peels off flat.
OpenVolume Calculator
Six shapes, with the litre conversion built in.
OpenSurface Area Calculator
Six shapes, and the ratio that explains why small things cool fast.
OpenPercentage Calculator
Every common percentage question in one place.
Open