Volume Calculator
Pick a shape, enter its measurements, and get the volume in cubic feet, cubic yards, cubic meters, liters and US gallons.
Volume formulas for common shapes
Volume is the amount of space inside a three-dimensional object. These are the formulas the calculator uses.
| Shape | Volume formula |
|---|---|
| Box (rectangular prism) | length × width × height |
| Cube | side³ |
| Cylinder | π × radius² × height |
| Sphere | 4⁄3 × π × radius³ |
| Hemisphere | 2⁄3 × π × radius³ |
| Cone | 1⁄3 × π × radius² × height |
| Pyramid (rectangular base) | 1⁄3 × base length × base width × height |
| Triangular prism | ½ × triangle base × triangle height × length |
Worked examples
ExampleBox. A raised bed 2 ft by 3 ft by 4 ft holds 2 × 3 × 4 = 24 cubic feet. That is about 179.5 US gallons or 679.6 liters.
ExampleCylinder. A round tank with a 1 m radius and a 1 m height holds π × 1² × 1 = 3.14 cubic meters, or about 3,142 liters.
ExampleSphere. A ball with a 3 in radius has a volume of 4⁄3 × π × 3³ = 113.1 cubic inches.
ExampleCone. A pile with a 3 ft radius and a 4 ft height has a volume of 1⁄3 × π × 3² × 4 = 37.7 cubic feet.
Gallons in a round tank or pool
For a round tank or above-ground pool, the volume is the area of the circle times the water depth. This table shows the volume for common diameters at a water depth of 4 feet.
| Diameter (ft) | Cubic feet | US gallons | Liters |
|---|---|---|---|
| 6 | 113 | 846 | 3,203 |
| 8 | 201 | 1,504 | 5,693 |
| 10 | 314 | 2,350 | 8,896 |
| 12 | 452 | 3,384 | 12,810 |
| 15 | 707 | 5,288 | 20,016 |
| 18 | 1,018 | 7,614 | 28,823 |
| 24 | 1,810 | 13,536 | 51,241 |
For a different depth, the volume changes in proportion. A pool filled to 3 ft holds three quarters of the figures above.
Common volume conversions
| Unit | Equals |
|---|---|
| 1 cubic foot | 1,728 cubic inches |
| 1 cubic foot | 7.48 US gallons, or 28.32 liters |
| 1 cubic yard | 27 cubic feet |
| 1 cubic meter | 1,000 liters, or 35.31 cubic feet |
| 1 US gallon | 3.785 liters, or 231 cubic inches |
| 1 liter | 1,000 cubic centimeters |
The calculator shows US gallons. An imperial (UK) gallon is larger, at about 4.546 liters, so the same volume is a smaller number of imperial gallons.
Tips for measuring volume
- Use the same unit for every measurement. Mixing feet and inches is the most common mistake.
- For containers, measure the inside, not the outside.
- For a shape that is not on the list, split it into simple shapes and add the volumes.
- For soil, gravel or mulch spread over the ground, our cubic yard calculator is quicker.
- To work out a flat surface instead, use the area calculator.
Results are estimates based on the numbers you enter. Confirm quantities with your supplier, installer or contractor before ordering.
Frequently asked questions
What is the difference between volume and area?
Area measures a flat surface in square units, such as square feet. Volume measures the space inside a three-dimensional object in cubic units, such as cubic feet.
How do I find the volume of a cylinder if I only know the diameter?
Choose “Cylinder (from diameter)”. The calculator halves the diameter to get the radius and then uses π × radius² × height.
How do I convert cubic feet to gallons?
Multiply cubic feet by 7.48 to get US gallons. One cubic foot is also about 28.32 liters.
How do I work out the volume of a rectangular pool or tank?
Multiply length by width by the average depth. A pool 32 ft long, 16 ft wide and 5 ft deep on average holds 2,560 cubic feet, which is about 19,150 US gallons.
How many liters are in a cubic meter?
One cubic meter is exactly 1,000 liters.
How do I find the volume of an irregular object?
Break it into simple shapes, work out each volume and add them together.