Step-by-step instructions
- Enter or select Radius.
- Tap Calculate.
- Review the result shown directly below the calculator.
Circle Calculator
Calculate area and circumference from radius.
How to use the Circle Calculator
Calculate area and circumference from radius.
What the inputs mean
- Radius
- Enter the value requested by this field label.
Formula or calculation method
Circle area uses πr² and circumference uses 2πr.
Example
Enter a realistic value for Radius and tap Calculate to see the computed result.
How to understand the result
Use the result as an estimate based on the values you entered. For planning decisions, double-check that the input units and assumptions match your real situation.
Tip: Keep all values in compatible units and use values from the same time period when the calculator compares two amounts.