Circle Calculator

Known measurement

Select one known positive measurement. Linear results use your chosen input length unit; area uses its square. When entering area, interpret it in squared units.

Results

Enter your values and select Calculate.

d=2r,C=2πr,A=πr2d=2r,\quad C=2\pi r,\quad A=\pi r^2

How it works

Select one known positive measurement. Linear results use your chosen input length unit; area uses its square. When entering area, interpret it in squared units.

d=2r,C=2πr,A=πr2d=2r,\quad C=2\pi r,\quad A=\pi r^2

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