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Circle Circumference Calculator

Circumference, diameter, and area of a circle.

Get the circumference, diameter, and area of a circle from any one of its radius, diameter, area, or circumference.

Daniel Oh By Daniel Oh
Published Last reviewed 1 min read

Inputs

Results

Enter values and click Calculate to see results.
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How to use this calculator

  1. Fill in the inputs above using the units you already have.
  2. Values update automatically as you type — no submit button needed.
  3. Hover any result row for the underlying formula and intermediate values.

Formula

C = 2πr, A = πr², d = 2r.

In depth

Get the circumference, diameter, and area of a circle from any one of its radius, diameter, area, or circumference.