Circle Sector Calculator
Enter a positive radius and an angle from 0° to 360°, then choose degrees or radians.
A QUICK WALKTHROUGH
How to use this tool
- Enter the radius and angle.
- Choose the angle unit.
- Review sector area and arc length in consistent units.
Formulas and units
Use one length unit for the radius. Area uses squared length units and arc length uses the same length unit. The angle may be entered in degrees or radians.
Validation
The radius must be finite and greater than zero. The angle must be greater than zero and no more than 360° (or 2π radians).
Geometry estimate
This is a mathematical geometry estimate for an ideal circular sector. Calculations happen locally in your browser.
GOOD TO KNOW
Common questions
Can I enter radians?
Yes. Select radians and enter a value greater than 0 and no more than 2π.