Circle Calculator
About Circle Calculator
Calculate circle diameter, circumference, and area.
How to Use
Calculate circle diameter, circumference, and area. Enter the Radius values and review the Diameter, Circumference, and Area outputs after you calculate.
- Open the calculator : Use Circle Calculator from the Math category.
- Check the inputs : Review the required values and any optional settings.
- Read the formula : Use the formula and notes below to understand how the result is produced.
Common Questions
What formula does the Circle Calculator use?
Area = ?r?. Circumference = 2?r.
Which measurement matters most in the circle calculator?
The radius controls every result, and the diameter is just twice the radius.
Inputs
- Radius
Outputs
- Diameter
- Circumference
- Area
Formula
area = pi*r^2, circumference = 2*pi*r