# Surface Area of Sphere

The **surface area of a sphere** is an area of its periphery. For example, if you count how much paint do you need to paint a **surface of a sphere**, you measure its radius and use a formula to calculate a surface of a sphere. The elementary unit of the surface area is one square metre, it means the second power of one metre (1 m^{2}).

## Surface Area of Sphere - formula

**Surface Area of Sphere** = Ludolph's number × diameter^{2}

or

4 × Ludolph's number × radius^{2}

S = π × d^{2} = 4 × π × r^{2}