Hemisphere Surface Area Calculator

Calculate the surface area of a hemisphere by entering the radius. A hemisphere is exactly half of a sphere including the flat circular base.

🌗 Hemisphere Surface Area

Formula

Total Surface Area: SA = 3πr²
Curved Surface: CSA = 2πr²
Base Area: BA = πr²
Where r is the radius of the hemisphere

Hemisphere Surface Area Formulas

Total Surface Area

SA = 3πr²

Includes curved surface and flat circular base

Curved Surface Area

CSA = 2πr²

Only the curved surface, excluding the base

Base Area

BA = πr²

Area of the flat circular base

Volume

V = (2/3)πr³

Volume of the hemisphere

Hemisphere Surface Area Examples

Example 1: Small Hemisphere

Given: Radius = 3 cm

Formula: SA = 3πr²

Solution: SA = 3π × 3² = 3π × 9 = 27π ≈ 84.82 cm²

Example 2: Medium Hemisphere

Given: Radius = 6 cm

Formula: SA = 3πr²

Solution: SA = 3π × 6² = 3π × 36 = 108π ≈ 339.29 cm²

Example 3: Large Hemisphere

Given: Radius = 10 cm

Formula: SA = 3πr²

Solution: SA = 3π × 10² = 3π × 100 = 300π ≈ 942.48 cm²

Hemisphere Surface Area FAQ

What is a hemisphere?

A hemisphere is exactly half of a sphere, created by cutting a sphere along a plane that passes through its center. It includes both the curved surface and the flat circular base.

How do you calculate hemisphere surface area?

Total surface area uses SA = 3πr², which includes the curved surface (2πr²) plus the flat base (πr²).

Why is the hemisphere formula 3πr²?

It combines the curved surface area (half of a sphere's 4πr² = 2πr²) plus the circular base area (πr²), totaling 3πr².

How does hemisphere surface area compare to a sphere?

A hemisphere has 3/4 the surface area of a complete sphere (3πr² vs 4πr²) because it includes the additional flat base.