Circumference Calculator
Calculate circumference, area, and other circle properties from radius or diameter
Circle Calculator
Calculate circle properties from radius or diameter
Circle Properties
Calculated circle measurements
Enter a radius or diameter to see results
Common Examples
Real-world circle calculations
12" Pizza
• Radius: 6 inches
• Circumference: 37.7 inches
• Area: 113.1 square inches
26" Bicycle Wheel
• Radius: 13 inches
• Circumference: 81.7 inches
• Distance per rotation: 81.7 inches
Circle Facts
Interesting properties of circles
Efficiency
Circles have the largest area for a given perimeter
Symmetry
Perfect rotational symmetry around center
Applications
Wheels, pipes, tanks, sports fields, gears
Pi (Ï€)
≈ 3.14159265359... (infinite decimal)