Circle
Calculator

Calculate circle properties — radius, diameter, circumference, and area — from any single known value, with arc length and sector area.

Solve From

Arc Angle

deg
dr

Circle Properties

Radius
5
Diameter
10
Circumference
31.4159
Area
78.5398

Formulas

d = 2r

C = 2πr

A = πr²

Arc = (θ/360) × 2πr

Sector = (θ/360) × πr²

Arc & Sector

Arc Length
7.854
Sector Area
19.635

Learn more

What makes pi so special, and why is it irrational?

Circle Calculator | ToolsCanvas