Find the volume, surface area, and diameter of a sphere from its radius. Enter the radius.
Usage Tip
Doubling a sphere’s radius multiplies its volume by eight (2 cubed).
surface area = 4 × π × radius²
It encloses the most volume for the least surface area of any shape.
Enter the radius; diameter is twice that.
Volume is in cubic units, surface in square units.
A sphere is fully described by its radius. The volume is four thirds times pi times the radius cubed, and the surface area is four times pi times the radius squared. The diameter is simply twice the radius.
Because volume depends on the cube of the radius, a ball with twice the radius holds eight times as much, while its surface area is only four times larger. Make sure you are entering the radius and not the diameter, which is the most common mistake. Spheres turn up in tanks, balls, bearings, and domes, and the volume formula is handy for estimating the capacity of rounded containers.