What is the formula for the volume of a cylinder?

The volume of a cylinder is pi times the radius squared, times the height. In symbols, V = pi r squared h. If you know the diameter, the radius is half the diameter.

How do I convert cubic metres to litres?

One cubic metre is 1,000 litres. So multiply cubic metres by 1,000 to get litres. A cylinder of 0.5 cubic metres holds 500 litres.

How do I find the volume of a tank or pipe?

A tank or pipe is a cylinder, so use the same formula. Measure the internal radius and the length or height, then multiply pi by the radius squared by the length. Use the internal measurements for capacity.

Cylinder Volume Calculator

This calculator works out the volume of a cylinder, the shape behind round tanks, pipes, posts, drums and tubes, so you can quickly find how much space or liquid one holds. Enter the radius or switch to diameter if that is what you measured, add the height, and choose whether your figures are in metres, centimetres or millimetres. The calculator applies the standard formula, volume equals pi times the radius squared times the height, converting everything to metres first so mixed units never cause an error. It returns the volume in cubic metres as the headline figure, with litres and cubic centimetres shown alongside, useful whether you are sizing a water tank, working out pipe capacity, checking how much concrete a post hole will take, or converting a drum's dimensions into a fill volume. Because the numbers update instantly as you type, it is easy to try a few different heights or diameters and compare the results before committing to a purchase or a dig. Remember to measure the internal radius or diameter for anything that needs to hold a set capacity, since wall thickness reduces the usable volume of a real tank or pipe. The result is a straightforward geometric calculation, so accuracy depends entirely on how precisely you measure the radius and height.

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Measurement

Radius / diameter

Height

Units

1.571 m³

Litres1,570.8

Cubic centimetres1,570,796

The formula

The volume of a cylinder is pi times the radius squared, times the height (V = pi r squared h). If you have the diameter, halve it to get the radius. All measurements must be in the same unit before you multiply, and the calculator converts your input to metres first.

Worked example

A water tank has a radius of 0.5 m and a height of 2 m. The volume is pi times 0.5 squared times 2, which is about 1.571 cubic metres, or 1,571 litres.

Frequently asked questions

How many litres in a cubic metre?

1,000. Multiply cubic metres by 1,000 to get litres.

Radius or diameter?

Either works. Switch the dropdown to diameter if that is what you measured, and the calculator halves it for you.

Who this calculator is for

This calculator is for anyone working out the volume of a cylinder, such as a tank, pipe, tube or drum.

What this calculator assumes

The radius or diameter and the height you enter.
The formula volume equals pi times radius squared times height.
All dimensions are in consistent units.
Results are rounded for display.

Related calculators

Cubic Metre Calculator: volume of a box shape.
Volume Conversion Calculator: convert volume units.
Square Metre Calculator: area in square metres.
Concrete Calculator: concrete volume and bags.

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