Volume Calculator: Simple and Powerful

Five shapes, five formulas

The dropdown swaps in the correct inputs and formula for each shape, so the numbers you enter run through standard geometry, not a generic approximation:

• Cube: volume = side³. A side of 5 gives 5³ = 125.00 cubic units.
• Sphere: volume = (4/3) × π × radius³. A radius of 3 gives (4/3) × π × 27 ≈ 113.10.
• Cylinder: volume = π × radius² × height. Radius 4, height 10 gives π × 16 × 10 ≈ 502.65.
• Cone: volume = (1/3) × π × radius² × height — exactly one-third of a cylinder with the same radius and height. Radius 3, height 9 gives (1/3) × π × 9 × 9 ≈ 84.82.
• Rectangular prism: volume = length × width × height. 4 × 3 × 2 gives 24.00.

Why the cone is exactly a third of the matching cylinder

This isn't a rounding coincidence — a cone and a cylinder that share the same base radius and height always have this 1:3 volume ratio, which is why the formulas differ only by that factor of 1/3.

Input validation

Every field requires a positive number greater than zero; entering 0, a negative number, or leaving a field blank returns "Please enter valid positive numbers" instead of a silently wrong result like a volume of 0 or a negative volume.

Units are whatever you entered

The result is labeled "cubic units," not a specific unit like cm³ or in³, because the calculator doesn't track which unit you used — if you entered measurements in inches, the output is in cubic inches; in centimeters, it's in cubic centimeters. Keep your inputs in one consistent unit before calculating.