Cylinder Volume Calculator

The formula

Volume = π × radius² × height

It is the area of the circular base multiplied by the height. Use the same unit for radius and height: in metres the result is in m³ (× 1,000 for litres); in centimetres it is in cm³, which are millilitres.

Worked examples

• A water tank 1 m in diameter (radius 0.5 m) and 1 m high: π × 0.25 × 1 = 0.785 m³, i.e. 785 litres.
• A drinks can with a 6.6 cm diameter (radius 3.3 cm) and 11.5 cm high: π × 10.89 × 11.5 ≈ 393 cm³. It is sold as 330 ml because the top and bottom are narrower and some headspace is left.
• A round above-ground pool 3.66 m across, filled to 0.9 m: π × 1.83² × 0.9 ≈ 9.5 m³ — about 9,500 litres to fill.

Radius or diameter?

The formula needs the radius, half the diameter. Using the diameter by mistake gives a volume four times too large. If you prefer the diameter: V = π × d² × h ÷ 4.

Reverse calculations

• Height for a given capacity: h = V ÷ (π r²). For 200 litres (0.2 m³) in a 0.3 m radius drum: 0.2 ÷ (π × 0.09) ≈ 0.71 m.
• Volume of a partly filled vertical tank: use the liquid height instead of the full height. A 785-litre tank filled to 40 cm holds π × 0.25 × 0.4 ≈ 314 litres.
• Pipes: the volume of water in 10 m of pipe with a 2 cm inner diameter is π × 0.01² × 10 = 0.00314 m³, about 3.1 litres.

Surface area

Total surface = 2πr² (two ends) + 2πrh (side). For the 1 m tank above: 1.57 + 3.14 = 4.71 m² — useful to estimate paint or insulation.

Horizontal tanks partly filled need a different calculation based on the circular segment of liquid. For pointed shapes, see the cone volume calculator.

Formulas and content last reviewed: October 2026 · About