Volume Calculator
This volume calculator handles the five shapes you actually meet on real projects: box, cylinder, sphere, cone and rectangular pool. Enter the dimensions in meters, centimeters, feet or inches and read the volume with instant conversions to liters, US gallons and cubic feet. An 8 x 4 m pool with 1.5 m of average depth holds 48 m³, or 48,000 liters.
Volume
1.571 m³
m³
1.571
Liters
1,570.8
US gallons
415
ft³
55.472
Examples
How to use
- 1
Choose the shape: box, cylinder, sphere, cone or pool.
- 2
Pick the unit your measurements are in (m, cm, ft or in).
- 3
Enter the dimensions asked for that shape, like radius and height for a cylinder.
- 4
Read the volume with conversions to m³, liters, US gallons and ft³.
The five volume formulas
The volume calculator applies the standard geometric formula for each shape and shows only the fields that shape needs:
| Shape | Formula | Inputs |
|---|---|---|
| Box | length x width x height | 3 dimensions |
| Cylinder | pi x radius² x height | radius, height |
| Sphere | 4/3 x pi x radius³ | radius |
| Cone | pi x radius² x height / 3 | radius, height |
| Pool (rectangular) | length x width x average depth | 3 dimensions |
Watch the radius. A 50 cm wide pipe has a radius of 25 cm, not 50, and using the diameter by mistake multiplies the result by 4 because the radius is squared.
Worked examples
Cylinder: a rainwater tank
A tank with a radius of 0.5 m and a height of 2 m holds pi x 0.5² x 2 = 1.571 m³, which converts to 1,571 liters or 415 US gallons. That is where this calculator earns its keep, since tank capacities are sold in liters or gallons while you measure the tank in meters.
Pool: how much water to fill it
A rectangular pool of 8 x 4 m with a shallow end at 1.2 m and a deep end at 1.8 m has an average depth of 1.5 m. The volume is 8 x 4 x 1.5 = 48 m³, or 48,000 liters (about 12,680 US gallons). Pool chemicals and pump sizes are specified against exactly this number.
Cone: a pile of gravel
Loose gravel dumped from a truck settles into a rough cone. A pile 3 m across (radius 1.5 m) and 1 m high contains pi x 1.5² x 1 / 3 = 2.36 m³. A cone holds exactly one third of the cylinder with the same radius and height, which is a handy sanity check when a result looks off.
Sphere: a round tank
A spherical tank only needs its radius. A 1 m radius gives 4/3 x pi x 1³ = 4.19 m³, or 4,189 liters. Double the radius and the volume grows eight times, to 33.5 m³, because the radius is cubed.
How the conversions work
The calculator computes the volume in your chosen unit, then converts through cubic meters, where 1 m³ equals 1,000 liters, 35.31 cubic feet and 264.17 US gallons. Because the unit is cubed, small unit mistakes explode. One cubic meter is a million cm³ and one cubic foot is 1,728 cubic inches, so entering centimeters while thinking in meters is the single most common source of absurd results.
If the result feeds a concrete order rather than a water volume, use the concrete calculator instead, since it adds the wastage margin and the bag counts on top of the raw geometry.
Parameters
Every field of this tool can be prefilled from the URL. Use these query parameters:
| Parameter | Type | Default |
|---|---|---|
| shape | box | cylinder | sphere | cone | pool | box |
| a | number | 2 |
| b | number | 1.5 |
| c | number | 1 |
| unit | m | cm | ft | in | m |
Example : https://www.veltotools.com/math/volume-calculator?shape=box&a=2&b=1.5&c=1
API
The same tool is available as a free JSON API, with the same parameters as above. No key, no sign-up.
Frequently asked questions
Related terms
Updated Jul 23, 2026