Outer faces and curved surfaces
Sphere Surface Area Calculator
Use the radius or diameter to find the area covering a sphere. The result is the full curved surface, rather than the area of a circle.
Enter your measurements
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Sphere surface area formula
For radius r, use A = 4πr². Since diameter d = 2r, the equivalent diameter formula is A = πd². Either input option gives the same result.
Example: diameter 10 ft
The radius is 5 ft. Area = 4 × π × 5² = 100π ≈ 314.16 ft², or approximately 29.19 m².
A sphere is not a flat circle
A flat circle with radius r has area πr². A sphere with that radius has four times that area: 4πr². Use the circle area calculator for a flat disc.
This tool calculates a complete sphere. It does not include a hemisphere, spherical cap or openings. To calculate enclosed space, use the sphere volume calculator.
Enter every length in the same unit. Results are rounded for display; calculations use unrounded values and the full precision of π.