Circle Calculator
Calculate area, circumference, radius, and diameter of a circle.
Results
Radius:
Diameter:
Circumference:
Area:
What is this Online Circle Calculator for?
The Circle Calculator helps you find all properties of a circle (Radius, Diameter, Circumference, Area) if you know just one of them.
How does it work?
It uses the mathematical constant Pi (π ≈ 3.14159) and standard geometric formulas to derive the unknown values from the known input.