Cylinder Cubic Footage Calculator

A cylinder cubic footage calculator returns the volume of a round space in cubic feet. It multiplies π by the radius squared, which is half the diameter squared, then by the height. A cylinder 3 ft in diameter and 5 ft tall holds 35.34 cubic feet.

Last reviewed September 2026Method & sources Report an error

Not to scale.

Volume

35.34 cu ft

Breakdown
Volume	35.34 cu ft

How to Calculate Cylinder Cubic Footage

A cylinder's volume is π × radius² × height. It is the circular cross-sectional area (from half the diameter) times the height.

Example: 3 ft diameter, 5 ft tall cylinder

A 3 ft diameter, 5 ft tall cylinder: 1. Cross-sectional area: π × (3 ÷ 2)² = π × 2.25 = 7.07 sq ft 2. Volume: 7.07 × 5 = 35.34 cu ft

What Is Cylinder Cubic Footage?

A cylinder cubic footage calculator finds the volume of a round space, such as a planter, storage bin, silo, or round footing form, in cubic feet. It is useful for figuring out how much material (soil, feed, concrete, or anything else) it holds or requires.

Cylinder Cubic Footage: Pros and Cons

Pros

Applies the exact cylinder volume formula directly, with no approximation
Works for any diameter and height, from a small planter to a large silo
Complements the Cylinder Cubic Yardage calculator for the same shape in the unit bulk material like concrete is ordered by

Cons

Doesn't convert to gallons for a liquid-holding tank. See the Tank Volume calculator for that unit
Doesn't account for a tapered cylinder (wider at one end than the other). That shape needs a different (frustum) volume formula
Assumes the full height and diameter are uniform. A cylinder with a domed top or bottom holds slightly more or less than this calculation

Cylinder Cubic Footage: What a Pro Checks

Check a bagged soil product's packaging for its coverage in cubic feet, then compare it against this calculator's volume figure to know how many bags a round planter or raised bed actually needs.
If your container has a domed or rounded top or bottom rather than flat ends, expect its actual capacity to differ slightly from this calculation, which assumes a uniform straight-sided cylinder.

Frequently Asked Questions

How do I calculate the volume of a cylinder in cubic feet?

Multiply π by the radius squared (half the diameter, squared) by the height. A 3 ft diameter, 5 ft tall cylinder is π × 1.5² × 5 = 35.34 cu ft.

How much soil does a round planter hold?

Calculate its volume using diameter and height (or fill depth, if not filling to the rim). That cubic feet figure tells you how much soil to buy. Most bagged soil lists its coverage in cubic feet on the packaging.

Does this work for a cylindrical concrete footing or pier form?

Yes, for the volume itself. A round sonotube form's volume follows the same cylinder formula. See the Cylinder Cubic Yardage calculator if you want the result directly in cubic yards for ordering ready-mix concrete.

What is the difference between this and the Tank Volume calculator?

The math is identical, since both are cylinder volume. Tank Volume converts the result to gallons for a liquid-holding container. This calculator stays in cubic feet, which is more useful for a dry-material application like soil, feed, or concrete.

How do I find the diameter if I only know the circumference?

Divide the circumference by π (about 3.14159). A cylinder with a 9.42 ft circumference has a diameter of about 9.42 ÷ 3.14159 ≈ 3 ft.

Measurement