Circle Radius from Area
Inverting the circle-area relation recovers a radius from a known surface area.
Circle Radius from Area
Circles · 1 input
How to use this calculator
- Enter area in cm².
- Select Calculate and keep the output unit with the answer.
Before you use the answer
Start with a dimensioned sketch and label the units beside every measurement. Distinguish the outer edge from an internal opening, and distinguish a radius from a diameter. A geometric model is most useful when the shape actually matches the assumptions in the formula.
This returns radius rather than diameter. A rounded source area limits the precision of the recovered dimension.
Does it save my inputs?
No calculation history is stored by this website. The calculator works locally in your browser. See the privacy policy for hosting and contact details.
Why might a result be approximate?
Measurement uncertainty, ideal-model assumptions and floating-point rounding can all matter. Displaying more digits does not improve the original measurement.
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