Learn & check

Find the Volume of the Cylinder

Understand what the answer means — cubic units, exact-π form, and why the radius is squared — then check it with the calculator.

Understanding the answer matters as much as getting it. This page clears up the questions that come with the find the volume of the cylinder — why volume is in cubic units, what the exact-π form means, and why the radius is squared — with the calculator on hand to test it.

Cylinders turn up everywhere once you start noticing them — a tin of beans, a scaffold pole, a rainwater barrel, the barrel of a pump. Because they all share the same simple geometry, one calculation covers the lot, and the only thing that really changes from job to job is the unit you read the answer in.

Using the calculator

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.

Getting an accurate measurement

If you can only reach the top, measure the diameter across the opening and halve it. Keep every measurement in the same system, and let the tool convert between units for you.

The maths in one line

The volume of a cylinder is:

V = π r² h

A worked example

Worked example. Take a cylinder with a diameter of 10 cm (so a radius of 5 cm) and a height of 25 cm. The base area is π × 5² = 78.54 cm², and multiplying by the height gives a volume of about 1.96 litres (1,963 cm³ · 0.52 US gallons).

For anything that holds liquid, measure the inside of the cylinder — the wall takes up space that the contents cannot.

Conversions use standard factors: 1 US gallon = 231 in³, 1 Imperial gallon = 4.54609 L, 1 litre = 1000 cm³.

What people work out next

To save you a second search, here are the related answers people most often want straight after this calculation:

What if I have the diameter, not the radius?

Toggle the base input to diameter and the tool halves it for you. There is also a circumference option for when that is all you were able to measure.

How do I find a missing dimension?

If you know the volume you need and one measurement, the reverse-solver returns the height, radius or diameter that matches it.

Can I get the weight too?

Tick estimate weight, pick a material, and the calculator multiplies volume by density to show the mass in kilograms and pounds.

What will the volume be in gallons or litres?

You do not have to choose up front. The result lists litres, US gallons, Imperial gallons, cubic feet and more together, so you can switch the main unit whenever you like.

Where people use this

A few of the jobs it gets used for:

Checking a geometry homework answer
Sizing a barrel, drum or planter
Estimating pipe or duct volume
Planning a DIY water feature

Getting it right

The commonest slip is using the diameter where the formula wants the radius, which on its own quadruples the base area. Close behind is mixing units, such as a radius in centimetres with a height in metres. Keep every length in the same unit, or let the tool convert, and double-check whether you measured to the centre or across the whole width. When a figure looks surprising, that width measurement is almost always where the problem is hiding, so re-read it first.

Getting the number in the unit you need

One number, many units. Whatever you enter, the result lists the same volume as litres, US gallons, Imperial gallons, millilitres, cubic centimetres, cubic inches, cubic feet, cubic yards and cubic metres at the same time. You almost never have to convert by hand: read the figure in the unit your job uses and copy any of the others straight from the breakdown. If you need a shareable version, the copy-link button preserves your exact inputs so a colleague opens the page with the same calculation already filled in.

What to work out next

Once you have your answer you may also want to work in volume formula cylinder volume circle vs cylinder. These related calculators pick up where this one leaves off:

Is the Volume of a Cylinder Squared or Cubed Volume of Cylinder in Terms of Pi What Is the Exact Volume of the Cylinder What Is the Volume of the Cylinder Below

To sum up, the whole job is two measurements and one formula. Enter them above, pick your unit, and you have an accurate figure plus every equivalent unit beside it. Keep a copy with the copy-result button, save the shareable link if someone else needs the same numbers, and use the history panel to compare a few options without starting from scratch.

Questions people ask

Is volume squared or cubed?

Volume is always cubic — it fills length, width and height. The radius is squared inside π r² only because that builds the flat circular base; the height supplies the third dimension.

What does 'volume in terms of π' mean?

It means leaving π in the answer instead of multiplying it out — for example 144π in³. It is the exact value, which the calculator can display via the 'Exact' precision setting.

How do I read the volume off a diagram?

Find the radius (or diameter) and the height on the figure, put them into V = π r² h in matching units, and compute. Enter the same numbers above to confirm your answer.

What is the formula for the volume of a cylinder?

The volume is V = π r² h — the area of the circular base (π r²) multiplied by the height (h). If you have the diameter instead of the radius, halve it first: r = d ÷ 2.

Do I use radius or diameter?

Either — just tell the calculator which you are entering. The radius is from the centre to the edge; the diameter is the full width across. The tool converts diameter to radius automatically.

What units can I use?

Any of millimetres, centimetres, metres, inches, feet or yards for the measurements, and you can read the result in litres, gallons, cubic feet, cubic inches and more.