ToolGrid AICircle Area and Circumference
Calculate a circle’s area, diameter and circumference from its radius.
Runs entirely in your browser — your selected files are not uploaded by this tool. Device-provided speech voices may use online services.
About this free circle area and circumference tool
Calculate a circle’s area, diameter and circumference from its radius. Calculators answer a defined arithmetic question using the values you supply. Keep units and currencies consistent, choose the correct starting amount and inspect the assumptions before using a result. Estimates do not replace a lender quotation, an official tax rate, a medical assessment or a jurisdiction-specific deadline rule.
A practical example
A concrete example uses radius in your chosen length unit: 3. The result is Diameter: 6 Circumference: 18.849556 Area in square units: 28.274334.
Before you rely on the result
Results use floating-point arithmetic and are rounded to six decimal places. Confirm units and required precision before using the result.