Sphere Surface Area Calculator

Enter the radius, diameter, surface area, or volume of a sphere and get every other measurement instantly, with the formula and worked steps shown.

A = 314.1593 r = 5 d = 10 centre V = 523.5988
Surface area —
Volume —
Radius —
Diameter —

How to Find the Surface Area of a Sphere

Fill in exactly one field — radius, diameter, surface area, or volume — and the rest are derived from it.

1

Enter one measurement

Type a single positive number into radius, diameter, surface area, or volume. Clearing a field or typing in another one resets the rest, so only one value drives the calculation at a time.

2

The calculator solves for the radius

Every formula starts from the radius: r = d / 2 from the diameter, r = √(A / 4π) from the surface area, or r = ∛(3V / 4π) from the volume. Once the radius is known, the other three measurements follow directly.

3

Read the result and steps

Surface area, volume, radius, and diameter all appear together, with the exact formula work shown below. Working with a flat circle instead? The Circle Area Calculator solves for its area and circumference the same way.

Frequently Asked Questions

What is the formula for the surface area of a sphere?
The surface area of a sphere is A = 4πr², where r is the radius and π is approximately 3.14159. So a sphere with radius 5 has a surface area of 4 × π × 5² = 4 × π × 25 ≈ 314.16 square units. If you only know the diameter, first halve it to get the radius (r = d / 2) before squaring. This calculator accepts any one of radius, diameter, surface area, or volume and derives the rest automatically.
What is the formula for the volume of a sphere?
The volume of a sphere is V = (4/3)πr³, where r is the radius. A sphere with radius 5 has a volume of (4/3) × π × 5³ = (4/3) × π × 125 ≈ 523.60 cubic units. Surface area and volume both come from the same radius, so once you know one of them you can work backward to find the radius and then compute the other.
How do you find the radius of a sphere from its surface area or volume?
From the surface area, solve A = 4πr² for r to get r = √(A / 4π). From the volume, solve V = (4/3)πr³ for r to get r = ∛(3V / 4π). For example, a surface area of 4π square units (≈12.566) gives r = √(4π / 4π) = 1. This calculator runs those inversions for you, then reports the radius, diameter, surface area, and volume together.
What is the difference between the area of a circle and a sphere?
A circle is flat and has one area, A = πr². A sphere is the 3D ball formed by spinning that circle, and it has two related measures: a surface area of A = 4πr² — exactly four times the circle's area — and a volume of V = (4/3)πr³. To work with a flat circle instead of a sphere, use the Circle Area Calculator.