Sphere Volume Calculator
Enter a radius and read the volume and surface area of a sphere instantly — from balls and tanks to bubbles and planets.
Two results at once
A single radius gives both the volume it encloses and the surface area of its outer skin.
Unit-agnostic
The radius can be in any unit — the volume comes out cubed and the surface area squared in that same unit.
What is a sphere volume calculator?
One radius, full geometry
A sphere volume calculator turns a single measurement — the radius, the distance from the centre to the surface — into the two numbers that describe a perfect ball: how much space it holds inside, and how much skin wraps around the outside. The volume follows V = 4/3 × π × r³ and the surface area follows A = 4 × π × r². Because both formulas depend only on the radius, you never need to measure anything else: a tennis ball, a storage tank, a soap bubble, and a planet all obey the same two rules.
Enter the radius and read the volume and surface area at once — no formula juggling required.
Cube the radius for the volume and square it for the surface area, then scale each by its constant.
V = 4/3 × π × r³ · A = 4 × π × r²The volume formula multiplies the cube of the radius by π and by 4/3 — a constant that comes from integrating the area of circular slices through the ball. The surface area takes the square of the radius, multiplies by π to get the area of one great circle, then multiplies by 4 because the full surface is exactly four such circles. Both constants are fixed, so the only thing you change is the radius.
Suppose you have a sphere with a radius of 5.
Cube the radius
5³ = 5 × 5 × 5 = 125.
Find the volume
4/3 × π × 125 = 523.598776 cubic units.
Find the surface area
4 × π × 5² = 4 × π × 25 = 314.159265 square units.
The two results scale very differently, and that is the most useful thing to remember. Volume grows with the cube of the radius, so doubling the radius makes the sphere eight times larger inside (2³ = 8), while the surface area grows with the square of the radius, so it only quadruples (2² = 4). That is why a slightly bigger ball holds far more than it looks, and why large tanks store volume so efficiently relative to the material in their walls. Use the volume when you care about contents — litres of water, mass of a planet, dosage in a capsule — and the surface area when you care about the skin: paint, coating, or heat loss. As a sanity check, the volume in cubic units is always larger than the surface area in square units once the radius passes 3, and the gap widens fast as the radius grows.
The formulas are exact, but they describe an ideal shape.
Perfect spheres and display rounding
The calculation assumes a perfect, mathematically smooth sphere. Real objects — slightly oval balls, dented tanks, or lumpy droplets — deviate from the ideal, so treat the result as a close estimate for anything that is only roughly spherical. Results are rounded to six decimal places, so values with long decimal tails may round the last digit, and the radius must be a positive number for the geometry to be defined.