Sphere measurements
The radius is the distance from the center to the surface. Diameter is twice the radius and must use the same length unit.
Example
For a sphere with radius 5, volume is 4/3 x pi x 125, or about 523.60 cubic units. The surface area is about 314.16 square units.
When volume matters
Use volume for capacity or space inside a sphere. Use surface area for coating, wrapping or exposure.
Limitations
The formula assumes a perfect sphere. Real containers, domes or balls may have seams, flattening or fittings that change usable volume.
Last reviewed: 2026-05-17