Mathematics is the queen of the sciences.C. F. Gauss

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Circle area

Calculate a circle from its radius, diameter or circumference.

6
Automatic

Enter known values

Fill in the fields below — the result will appear alongside.

Live diagram of the known values
r
Radius
r
m

Formulas

r=d2r=\frac d2r=C2πr=\frac{C}{2\pi}d=2rd=2rC=2πrC=2\pi rA=πr2A=\pi r^2

How it works

Choose one source measurement to calculate radius, diameter, circumference and area with automatic unit conversion.

The selected measurement is converted to radius, then all other circle properties follow from π.

Examples

Radius 25 cm{"radius":{"unit":"cm","value":25},"source":"radius"}

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