Surface Area of a Sphere

The surface area of a sphere calculator finds the Area of a sphere from its Radius, or the radius from the area. Enter one value and the other is calculated automatically.

How it works

The surface of a sphere is exactly four times the area of a circle with the same radius:

\[ Area = 4 \pi \times Radius^2 \]

To find the radius, divide the area by 4π and take the square root. If you know the diameter, divide it by 2 to get the radius.

Example

A sphere has a radius of 3. The surface area is 4 × π × 3² = 36π ≈ 113.1. If you know the area is 36π, leave the radius empty and the calculator finds 3.