Geometry

Circle Calculator

Lets users solve and check circle instantly with formula, steps and examples — no manual math.

Enter your details

units
Your result
Area
78.5398 sq units

Area = πr² = 78.54; circumference = 2πr = 31.42.

Circumference
31.4159 units
Diameter
10 units

About this calculator

A circle's area = πr², circumference = 2πr, diameter = 2r. Enter the radius to get all three.

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