Circle Area Calculator
Calculate a circle's area from its radius using πr².
How to use
- Enter radius r.
- Calculate to obtain π×r².
Capabilities and scope
A single radius produces the two-dimensional area inside the circle.
How it works
It uses A = πr².
Example
A radius of 3 gives an area of about 28.2743 square units.
Useful for
- Find the area of a circular floor or plate
- Check a radius-based geometry calculation
Before you use it
- The result is in squared input units; no unit conversion is performed automatically.
Frequently asked questions
What if I know the diameter?
Divide the diameter by two and enter that value as the radius.