⚪ Geometry Tool
Circumference Calculator
Circle · Radius · Diameter
Calculate circumference, diameter, and area of a circle. Enter radius or diameter, choose units, and get instant results with formulas.
circumference calculator
circle circumference
diameter to circumference
radius to circumference
Calculator
Input Mode
๐ Radius (r)
๐ Diameter (d)
Radius (r) units
Circumference (C)
—
units
Area (A)
—
sq units
r = 5
Circumference = 2ฯr = ฯd
๐ Formulas used:
• Circumference = 2 × ฯ × radius = ฯ × diameter
• Area = ฯ × radius²
• ฯ (Pi) ≈ 3.141592653589793
With radius = 5 units: C = 2ฯ×5 = 31.42 units, A = ฯ×25 = 78.54 sq units
• Circumference = 2 × ฯ × radius = ฯ × diameter
• Area = ฯ × radius²
• ฯ (Pi) ≈ 3.141592653589793
With radius = 5 units: C = 2ฯ×5 = 31.42 units, A = ฯ×25 = 78.54 sq units
Reference
Common Circle Dimensions
| Radius (r) | Diameter (d) | Circumference (C) | Area (A) |
|---|---|---|---|
| 1 cm | 2 cm | 6.28 cm | 3.14 cm² |
| 5 cm | 10 cm | 31.42 cm | 78.54 cm² |
| 10 cm | 20 cm | 62.83 cm | 314.16 cm² |
| 1 m | 2 m | 6.28 m | 3.14 m² |