cube volume calculator
Calculate a cube's volume in cubic feet, cubic yards, gallons, and liters from a single side length — for cube-shaped forms and tanks.
A cube has all three sides equal, so volume takes just one measurement. Enter the side length and get volume in cubic feet, cubic yards, gallons, and liters.
How this calculator works
Cube volume is the side length cubed — side times side times side.
Formula: Cubic feet = side³. Cubic yards = ft³ ÷ 27. Gallons = ft³ × 7.48052. Liters = ft³ × 28.3168.
Worked example
A cube with a 3 ft side:
- Cubic feet: 3³ = 27.00 ft³
- Cubic yards: 27 ÷ 27 = 1.000 yd³
- Gallons: 27 × 7.48052 ≈ 202.0 gal
- Liters: 27 × 28.3168 ≈ 764.6 L
Reference
| Side (ft) | Cubic feet |
|---|---|
| 2 | 8.00 ft³ |
| 3 | 27.00 ft³ |
| 4 | 64.00 ft³ |
How to measure
Measure one side of the cube; since all sides match, that single number is enough. This applies to concrete test cubes, cube-shaped storage bins, water storage totes, and cube planters. If your box doesn’t have three equal sides, use the Rectangular Prism Volume Calculator instead.
Frequently asked questions
What's the formula for cube volume?
Volume equals the side length cubed: V = s³, or side × side × side. Since all three dimensions are equal, only one measurement is needed.
How is a cube different from a rectangular prism?
A cube is a special case of a rectangular prism where length, width, and height are all identical. If your sides aren't all equal, use the Rectangular Prism Volume Calculator instead, which takes three separate measurements.
Where does a cube shape actually come up in construction?
Concrete test cubes (used to check compressive strength), cube-shaped storage bins, water storage cubes (IBC-style totes are close approximations), and cube planters are common real-world uses.
Why does volume increase so fast when the side length grows?
Because the side is cubed, doubling it multiplies volume by 8, not 2. A 4 ft cube holds eight times as much as a 2 ft cube, even though the side is only twice as long.
How do I check a standard concrete test cube's volume?
A common lab test cube is 6 inches (0.5 ft) per side: 0.5³ = 0.125 ft³. Enter 0.5 as the side length to confirm.
How do I convert the cubic feet result to gallons for a cube tank?
Multiply cubic feet by 7.48052, which the calculator already does — that's the standard conversion for cubic feet to US gallons.
Estimates only. Verify quantities with your supplier before purchasing.