Circle Area Calculator — Area from Radius
CalculatorA circle area calculator applies πr² to find the area of a circle from radius r.
What is it
Circle area is the size of the plane inside a circle. Given radius, multiply pi by the square of the radius.
A = πr²
How to use
- 1Enter radius r.
- 2Press calculate.
- 3Check the circle area.
Reference
| Radius | Area |
|---|---|
| 10 | 314.159265 |
| 5 | 78.539816 |
Sources & standards
- MDN Web Docs: Client-side web APIs - MDN Web Docs
FAQ
What is the area of a circle with radius 10?
π×10² is about 314.159265.
Is circle area input sent to a server?
No. This tool runs in your browser and does not send input to a server.