Sphere surface area
Sphere surface area S = 4πr²: enter the radius to get the surface plus volume, diameter and equator length; values are rounded to 6 decimals and a non-positive radius is rejected.
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Result
One quantity per line, ready to copy.
Enter a radius to calculate
What this tool does
- Check the sphere surface area and get the surface area and equator length for packaging, coating or wire cutting.
- Compare how volume grows with radius — it scales with the cube, so doubling the radius multiplies the volume by eight.
- Verify the formulas: surface 4πr², volume 4πr³/3.
Example
Input
2
Output
半径 2 的球表面积：50.265482 体积 4πr³/3：33.510322 直径 2r：4 赤道周长 2πr：12.566371 长度单位 u，面积 u²，体积 u³
At radius 1 the volume is 4π/3 ≈ 4.188790, the surface 4π ≈ 12.566371 and the equator 2π ≈ 6.283185 — all canonical values.
Frequently asked questions
How does volume scale with radius?
Volume is proportional to the cube of the radius: going from 1 to 2 changes the volume from 4.19 to 33.51, exactly eight times. That is also why small spheres have proportionally more surface.
How do I read the units?
If the radius is in a length unit the surface is in square units and the volume in cubic units. The tool does not convert, so an input of 1 metre gives square and cubic metres.
Why is 0 rejected?
A zero radius collapses the sphere into a point — the formula still evaluates but the result is meaningless. Non-positive input is rejected instead of silently returning 0.
Keywords：圆球表面积Sphere surface area球sphere几何计算geometry表面积