Circle Calculator
Calculate area, circumference, radius, and diameter from any known value
Inputs
Enter any one value to calculate the rest:
cm²
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Results
Enter values to see results
Formulas
Circumference: C = 2πr = πd
Area: A = πr²
Diameter: d = 2r
Note: Calculations are provided as-is for educational and planning purposes. For critical applications, always verify results independently.
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