Cubic Yards of a Cylinder

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.

The formula behind it

The volume of a cylinder is:

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).

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

Follow-on questions, answered

The figure above is usually the start, not the finish. These are the questions that tend to come next, answered here so you do not have to run another search:

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.

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.

Common uses

A few of the jobs it gets used for:

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

Where people go wrong

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.

Reading and converting your result

Because volume units are where most errors creep in, the tool does the converting for you. Enter your measurements once and every common unit appears together, from millilitres up to cubic metres and across to US and Imperial gallons. Pick whichever the task calls for and lift the rest from the list; nothing needs a second calculation. The result also updates live as you change a measurement, so you can compare two sizes quickly without starting over.

What to work out next

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:

In short: measure the width and the height, keep them in the same unit, and the tool turns them into a volume you can read in litres, gallons, cubic feet or anything else, with the working shown so you can trust it. If a result ever looks off, re-enter the measurement you are least sure of, or switch to the diameter input and let the tool halve it for you, which catches the most common error before it matters.

Good to know