What is the formula for the volume of a cylinder?

V = πr²h — the area of the circular base (πr²) multiplied by the height. It works for any unit, as long as radius and height use the same one.

Should I leave π in the answer?

Exact answers keep π: 90π cm³, say. Decimal answers substitute π ≈ 3.14159: about 282.74 cm³. Homework often wants the exact form; real-world estimates want the decimal — this calculator gives you both.

I have the diameter, not the radius — what now?

Halve it. The radius is half the diameter, so a 6 cm diameter cylinder has r = 3 cm.

How is this related to the volume of a box?

It is the same idea — base area times height. The only difference is the base: a rectangle for a box (l × w), a circle for a cylinder (πr²).

Geometry

Cylinder Volume Calculator

Radius and height in, volume out — with the three moves of V = πr²h written out, and the answer in both exact π form and decimals.

Your numbers

Radius

Height

Worked solution

Volume of the cylinder

≈ 282.74 u³

exactly 90π u³ — base area 9π × height 10

V = πr²h: the base holds 9π, stacked 10 high, for 90π ≈ 282.74 cubic units.

The working

3 steps

Square the radius
r² = 3 × 3 = 9
Find the area of the circular base
base = π × 9 = 9π ≈ 28.27
Stack that area through the height
Volume is base area × height — every thin slice through the cylinder is another copy of the base.
V = 9π × 10 = 90π ≈ 282.74
Exact (in terms of π)
90π u³
Decimal (π ≈ 3.14159)
282.74 u³

Works instantly in your browser — nothing is uploaded, and the URL keeps your numbers so you can share the exact worked example.

Litres, pints and other conversions

One litre is exactly 1,000 cubic centimetres, so divide a cm³ answer by 1,000 to get litres — a 90π cm³ can holds about 0.28 L. For cubic metres to litres, multiply by 1,000 instead.