What is circumference?

The circumference is the perimeter of a circle, the total distance around its edge. It is a little more than three times the diameter. You find it with the rule circumference = π × diameter, where π (pi) is about 3.14.

Examples

• A circle with a diameter of 10 cm has a circumference of about 3.14 × 10 = 31.4 cm.
• Circumference = π × diameter.
• Doubling the diameter doubles the circumference.

Quick facts

• Circumference is just the special name for a circle's perimeter.
• The circumference is always about 3.14 times the diameter.