Cubic Yards in a Cylinder Calculator

The maths in one line

The volume of a cylinder is:

A worked example

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).

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

Using the calculator

1. Measure across the circular end — the diameter or radius.
2. If you measured the diameter, halve it to get the radius r.
3. Square the radius and multiply by π to get the base area.
4. Multiply the base area by the height h: V = π r² h.
5. 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.

What people work out next

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

How many cubic feet is that?

One cubic yard is 27 cubic feet, and the cubic-foot value appears in the breakdown, so you can cross-check a concrete order both ways.

How much ready-mix should I order?

Round columns and footings are priced by the cubic yard; it is normal to add about 5 to 10 percent on top of the geometric figure for spillage and uneven ground.

What is it in cubic metres?

One cubic yard is about 0.765 cubic metres, shown alongside the result for metric suppliers.

Do I measure the form in feet or inches?

Either works. Enter inches if that is how the round form was measured and the tool converts to feet, then to cubic yards, before you order.

Getting it right

Two things trip people up: squaring the wrong number, and forgetting that the answer is cubic. If a result looks four times too big or too small, you have probably swapped radius and diameter somewhere, so it is always worth re-reading the measurement you are least sure of. It also helps to glance at the equivalent units; if the litre and gallon figures are both off by the same factor, the input is the culprit, not the maths.

Getting the number in the unit you need

Showing every unit at once is about speed and safety: you see the answer in litres, gallons and cubic feet side by side, so there is no chance of applying the wrong conversion factor. Change the output unit at the top to make any of them the headline figure, switch the precision to exact if you want the value in terms of pi, and use copy-result to paste a tidy summary wherever you need it.

Keep going

Once you have your answer you may also want to work in cubic feet tank capacity gallons. These related calculators pick up where this one leaves off:

When this comes in handy

It comes in handy across quite different tasks:

• Ordering ready-mix for cylindrical piers
• Estimating fill for round forms
• Bulk material planning on a job site

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.

Frequently asked questions