RapidCheck

Area of a Circle Calculator

Find the area of a circle from its radius.

Last updated: 25 Aug 2026

Quick answer

The area of a circle is π × radius². For example, a radius of 7 gives an area of about 153.94 square units. Enter the radius above to calculate the area.

Find the area of a circle using A = π × r². Enter the radius in any unit; the area is in that unit squared.

How to calculate the area of a circle

  1. 1 Enter the radius of the circle.
  2. 2 We apply A = π × r².
  3. 3 The area appears instantly.

Frequently asked questions

What is the formula for the area of a circle?
Area = π × radius², where π ≈ 3.14159.
How do I find area from diameter?
Halve the diameter to get the radius, then apply πr².
What units is the area in?
The same unit as the radius, squared (e.g. cm → cm²).

Related checkers

Circumference Calculator Area of a Rectangle Calculator Area of a Triangle Calculator