Math & Statistics
Circle Calculator
Calculate radius, diameter, circumference and area of a circle.
TOOL 27
Enter your values
Use the fields below to calculate your result.
Result
78.539816
Diameter10
Circumference31.415927
Area78.539816
Formula: Diameter = 2r; Circumference = 2πr; Area = πr².
How to use this calculator
What to enter
Enter or select the following as requested: Radius. Follow the units, valid ranges, examples, and options displayed beside each field.
What the result means
The result is calculated from the geometric measurements, equation coefficients, coordinates, angle, or statistical values entered. Check sign conventions, units, angle mode, coordinate order, valid domains, and whether multiple solutions are possible.
When to use it
Use this to solve or verify a math problem or measurement. Keep units consistent and review any stated domain restrictions or rounding before using the result in another calculation.