Circle Calculator Guide
Use this calculator for quick circle measurements.
How the Formulas Work
Circle area is pi x radius squared, and circumference is 2 x pi x radius. If you only know the diameter, remember the radius is half of it before calculating.
Common Uses
Common in geometry coursework, but also useful for practical tasks like estimating material needed for circular tables, pipes, or garden beds.
Important Note
The tool will use the radius first if both radius and diameter are provided.