Online circular area calculator

1. This tool can calculate the area of a circle using its circumference, radius, or diameter.

2. Calculation formulas:

(1) Calculation using the radius: Area of a circle = π × radius².

(2) Calculation using the diameter: Area of a circle = π × diameter² ÷ 4.

(3) Calculation using the circumference: Area of a circle = circumference² ÷ 4π.

4. Note: If the number of decimal places in the result of this tool exceeds the set number of decimal places, the result will be rounded.