This free online volume calculator finds the volume of a cube, rectangular box, sphere, cylinder, or cone. Choose your shape, enter its dimensions, and get an instant, accurate volume calculation.
How to Use the Volume Calculator
Select your "Shape" - cube, rectangular box, sphere, cylinder, or cone.
Enter the required dimensions for that shape (e.g. Side for a cube, Length/Width/Height for a box, Radius for a sphere, or Radius and Height for a cylinder or cone).
Click "Calculate" to compute the volume.
Review the "Volume" result shown below the button.
Volume Formulas With Sample Answers
Volume is the amount of space a solid occupies. The calculator applies the formula for the shape you pick and rounds to 3 decimal places. Entering the example values shown in the form gives:
Shape
Formula
Sample input
Volume
Cube
a³
a = 3
27
Rectangular box
l × w × h
5 × 4 × 3
60
Sphere
(4/3)πr³
r = 3
113.097
Cylinder
πr²h
r = 3, h = 5
141.372
Cone
(1/3)πr²h
r = 3, h = 5
47.124
The cylinder and cone rows show a useful relationship: a cone holds exactly one third of a cylinder with the same base and height (141.372 ÷ 3 = 47.124). A sphere fills two thirds of the smallest cylinder that encloses it.
Turning Volume Into Litres
The answer is in cubic units of whatever you entered. To find how much liquid a container holds, convert with these exact or standard factors:
Example: a rectangular underground sump measuring 2 m × 1.5 m × 1.2 m has a volume of 3.6 m³, which is 3,600 litres. A cylindrical drum with a radius of 0.3 m and a height of 0.9 m holds about 0.2545 m³, or roughly 254 litres. Remember these are inside dimensions; measuring the outside of a thick-walled tank overstates its capacity.
Tips for Accurate Results
Use the radius, not the diameter. Because the radius is squared or cubed, entering a diameter makes a cylinder four times and a sphere eight times too large.
Keep every measurement in one unit. Mixing a height in centimetres with a radius in metres gives a meaningless answer.
For concrete, earthwork or grain, the volume of the shape is only the starting point. Site estimates usually add an allowance for wastage, compaction or bulking, which depends on the material and should come from your engineer or supplier.
Irregular objects can often be split into simpler shapes, for example a silo as a cylinder with a cone on top. Calculate each part separately and add them.
If you entered dimensions in metres, multiply the result by 1,000. If you used centimetres, divide by 1,000. If you used feet, multiply by about 28.317.
For a cone with radius = 3 and height = 5, the volume is (1/3) × π × 3² × 5 ≈ 47.124 cubic units.
A sphere's volume, (4/3)πr³, depends only on its radius, while a cylinder's volume, πr²h, also depends on its height - a cylinder with the same radius as a sphere but tall enough will hold more volume.
For a cylinder or cone of the same height, the volume becomes four times larger, because the radius is squared. For a sphere it becomes eight times larger, because the radius is cubed. Doubling only the height of a cylinder or cone simply doubles its volume.