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Perimeter of Circle Calculator

Find the perimeter (boundary length). Free online calculator with instant results — no login needed.

Radius

Perimeter

What is the Perimeter of Circle Calculator?

Find the perimeter (boundary length). Free online calculator with instant results — no login needed.

Enter your values above and the result updates instantly. Sum of all sides of the shape.

Circumference = 2 π r

Perimeter

Difference from area?

Perimeter is the boundary; area is the surface inside.