How do I calculate the surface area of a sphere?

Select area as the unknown value and enter the radius. The tool uses 4 × π × radius² and displays area in mm².

Can I find a sphere’s radius from its surface area?

Select radius as the unknown and enter the area. The inverse formula is the square root of area divided by 4π.

Enter radius, which is half the diameter. Using the full diameter as radius makes the calculated area four times too large.

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Formula

area = 4 × π × radius²

Calculate a result with Area of a Sphere from the values you enter. Enter the required values, adjust the options, and review the calculated result.

This tool runs open-source code from OmniTools (MIT License). See open-source credits.

Sphere Area Calculator solves sphere surface area or radius with 4 × π × radius².

It returns about 1256.637 mm². The calculation runs in your browser. Processing runs in the browser.

Input: radius = 10

Settings: Sphere Area Calculator: Unknown: area; length unit: millimetres.

Result: It returns about 1256.637 mm².

Sphere Area Calculator: The displayed area unit is mm².
Sphere Area Calculator: Using diameter as radius makes the area four times too large.
Sphere Area Calculator: It does not model thickness or irregular surfaces.