Circle Area
Calculate the exact area enclosed by a circle with a single radius measurement. Enter any radius value and the calculator applies A = πr² to return the area in perfectly matched square units for flooring, landscaping, crafts, and geometry homework.
Educational purposes only. Not professional advice.
Examples
- A garden bed with a 3 m radius covers 28.27 square meters.
- A circular pizza stone with a 14 in radius has 615.75 square inches of surface.
- A fountain basin radius of 2.5 ft equals 19.63 square feet of area.
FAQ
What formula is used?
The area equals π times the radius squared.
Can I use the diameter instead?
Yes. Divide the diameter by two to obtain the radius before calculating.
Which units are supported?
Any length unit works; the result uses the squared version of that unit.
What if the radius is zero?
A radius of zero yields an area of zero.
How can I convert the area to square feet or square meters?
First ensure the radius is entered in the unit you prefer. If you need to convert afterward, multiply or divide by the appropriate conversion factor (for example, 1 m² = 10.7639 ft²).
Additional Information
- Keep units consistent—if the radius is entered in centimeters, the result is in square centimeters.
- π (pi) is approximated as 3.141592653589793 to deliver high-precision results.
- To use the diameter, divide by two to find the radius before running the calculation.
- Need circumference too? Multiply 2 × π × radius to find the perimeter of the same circle.