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Volume formula calculator
The cylinder volume formula, what each symbol means, and a worked example you can copy — plus a live calculator to check your own numbers.
There is really only one formula to remember, and this page makes the volume formula calculator stick. You will see the equation, what each letter stands for, the diameter version, and a worked example — then a calculator to try it yourself.
How to work it out
- Measure across the circular end — the diameter or radius.
- If you measured the diameter, halve it to get the radius r.
- Square the radius and multiply by π to get the base area.
- Multiply the base area by the height h: V = π r² h.
- Convert the result into your preferred unit above.
Worked example. Take a cylinder with a diameter of 20 cm (so a radius of 10 cm) and a height of 40 cm. The base area is π × 10² = 314.16 cm², and multiplying by the height gives a volume of about 12.57 litres (12,566 cm³ · 3.32 US gallons).
For anything that holds liquid, measure the inside of the cylinder — the wall takes up space that the contents cannot.
Every volume formula page
Each page below targets a specific question and opens with the calculator ready to go:
Questions people ask
What is the cylinder volume formula?
V = π r² h. Using diameter, it becomes V = π (d/2)² h, which is the same as V = π d² h ÷ 4.