Circle Circumference Calculator
Calculate the circumference of a circle using radius or diameter. Perfect for geometry, engineering, and circular measurements.
Calculate Circumference
Enter either the radius or diameter of your circle:
Circle Circumference
The circumference of a circle is the distance around its outer edge. It's also known as the perimeter of the circle.
Circumference Formulas
If you know the radius:
Circumference = 2 × π × radius
If you know the diameter:
Circumference = π × diameter
Note: π (pi) ≈ 3.14159
Understanding the Relationship
The diameter is always twice the radius:
Diameter = 2 × Radius
Common Circumference Values
| Radius | Circumference | Real-world Example |
|---|---|---|
| 1 unit | ≈6.28 units | Small coin |
| 5 units | ≈31.42 units | Dinner plate |
| 10 units | ≈62.83 units | Beach ball |
Example Calculation
For a circle with radius 5 cm:
Circumference = 2 × π × 5 = 2 × 3.14159 × 5 = 31.42 cm
Applications
Circumference calculations are used in:
- 🏗️ Engineering: Designing circular components
- 🎨 Design: Creating circular patterns and layouts
- 🏃 Sports: Measuring running tracks and playing fields
- 🔧 Manufacturing: Calculating material requirements for circular objects
💡 Tip: Remember that circumference is the linear distance around the circle, while area measures the space inside the circle.