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Surface Area of Sphere Calculator

Online sphere calculator: enter the radius r to get the surface area S=4πr² and volume V=(4/3)πr³.

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S=4πr², V=(4/3)πr³
r
Positive

📖 Tutorial | Sphere

1. Definition
A sphere has surface area S=4πr² and volume V=(4/3)πr³, where r is the radius.
2. Formula & Notation
rRadius
3. Properties & Laws
  • S=4πr², V=(4/3)πr³;
  • Doubling r gives ×4 area, ×8 volume;
  • Area equals the circumscribed cylinder lateral area;
  • A sphere has no planar net.
4. Steps
  1. Enter r (positive);
  2. Click "Calculate";
  3. Or click "Load Example".
5. Worked Examples
Example: r=3 gives S=36π≈113.097, V=36π≈113.097.
6. Common Pitfalls
Factors 4 vs 4/3;
Mind r² and r³;
r=√(S/4π).

❓ FAQ | Sphere

Area?
4πr².
Volume?
(4/3)πr³.
Double r?
×4, ×8.
Cylinder?
Archimedes relation.
Net?
Cannot be flattened.
r=3?
Coincidence.
Diameter d?
r=d/2.