Area of a circle calculator

Radius

Diameter

Circumference

Area = 2.1² × π = 13.854423602331 meters²

The area of a circle calculator will help you calculate the surface of a circle using the radius, diameter or the circumference.

How do you calculate the area of a circle with the radius?

To calculate the area of your circle, you can multiply the square of a radius by pi and get the area of your circle.

Area = radius² × π

Example: You want to know what the area of a circle with a radius of 1.5 meter is, the formula would look like this: 1.5² × π = 7.07 m2

The radius of a circle is from the centre of the circle to the circumference of the circle. In the image below, the red line indicates the radius.

To calculate the area of your circle, you can multiply the square of a diameter divided by 2 by pi and get the area of your circle.

Area = (diameter / 2)² × π

Example: You want to know what the area of a circle with a diameter of 1.2 meter is, the formula would look like this: (1.2 / 2)² × π = 1.13 m2

The diameter of a circle is the distance across a circle through the centre. In the image below, the red line indicates the diameter.

To calculate the area of your circle, you can multiply the square of a circumference by 4 pi and get the area of your circle.

Area = circumference² × 4π

Example: You want to know what the area of a circle with a circumference of 38.5 meter is, the formula would look like this: 38.5² × π = 117.95 m2