Cubic Feet Calculator
Find the volume of a rectangular space or cylinder in cubic feet and convert it to other volume units.
How to use the Cubic Feet Calculator
- Choose the shape.
- Enter the length and pick its unit.
- Enter the width and pick its unit.
- Enter the diameter and pick its unit.
- Enter the height / depth and pick its unit.
- Enter the quantity.
- Press Calculate. The result updates automatically as you type, and you can switch the result unit at any time.
About the Cubic Feet Calculator
Cubic feet measure three-dimensional space: how much a room, crawlspace, bin, planter or tank holds. Builders use it for concrete and fill, HVAC designers for room air volume, and gardeners for bagged soil, which is labeled in cubic feet.
When measurements are in inches, you can also multiply them directly and divide the cubic inches by 1,728. For a room's air volume, measure the ceiling height at several points if the ceiling is sloped and use the average.
Formula
Box: Volume = Length × Width × Height
Cylinder: Volume = π × (Diameter ÷ 2)² × Height
Convert all measurements to feet first (inches ÷ 12). 1 ft³ = 1,728 in³ = 7.48 US gallons = 28.32 liters, and 27 ft³ = 1 yd³.
Example calculation
Using the default values:
- Shape = Rectangular box / room
- Length = 4 ft
- Width = 3 ft
- Height / depth = 2 ft
- Quantity = 1
the calculator returns:
- Volume: 24 ft³
- Cubic yards: 0.889 yd³
- Cubic meters: 0.68 m³
- US gallons: 179.5 gal
Frequently asked questions
How do I calculate cubic feet?
Multiply length × width × height, all in feet. A 4 × 3 × 2 ft box is 24 cubic feet.
How do I convert cubic inches to cubic feet?
Divide by 1,728 (12 × 12 × 12).
How many gallons are in a cubic foot?
One cubic foot holds about 7.48 US gallons of liquid.
Last updated: · Category: Construction calculators