Online Calculators > Math Calculators > Circle Calculator
Circle Calculator
Circle Calculator to calculate the area of a circle, circumference, diameter and radius. Given any one variable of a circle you can calculate the other 3 unknowns with our online circle calculator.
Radius: 

Diameter: 

Circumference: 

Area: 

Circle Formula
Following are the circle formula to calculate area of a circle, circumference, diameter and radius.
Circumference of a Circle Formula = Π * 2 * radius,
Area of Circle Formula = Π*radius^{2},
Diameter of Circle Formula = 2*radius
where Π = approximately equal to 3.14159
