Circle Area Calculator

To calculate the area of a circle:

• select defined data - radius, diameter or circumference;
• enter the value of data;
• select units of measurement - meter (m), centimeter (cm) or millimeter (mm);
• select the value of π;
• select in which units you want to get the area - square meters (m²), square centimeters (cm²) or square millimeters (mm²).

You can input only integer numbers or fractions in this online calculator. More in-depth information read at these rules.

If you have any difficulties with units conversion, you can use the length converter and area converter.

Circle is a simple shape consisting of those points in a plane that are equidistant from a given point, the centre. The distance between any of the points and the centre is called the radius.

The formulas for calculating of circle area:

• A = π r²
• A = 14 π d²
• A = l²4π

where A - circle area,
r - circle radius,
d - circle diameter,
π = 3.141592.