Circle Calculator
Find the radius, diameter, circumference and area of a circle from any one of them.
- Radius
- 5
- Diameter
- 10
- Circumference
- 31.41592654
- Area
- 78.53981634
What is Circle Calculator?
A circle is fully described by one number. If you know the radius, the diameter, the circumference or the area, you can find the other three.
What this tool does
Choose which value you know and enter it. The calculator uses pi to find the radius, diameter, circumference and area.
How to use it
- Choose what you know.
- Enter the value.
- Read the other three values.
Did you know?
- The diameter is twice the radius, and the circumference is pi times the diameter.
- Pi is about 3.14159 and has been calculated to over 100 trillion digits.