What is circumference?

Definition

The circumference is the distance around a circle. It equals π times the diameter, or 2πr.

Example

A circle with radius 5 cm has circumference about 2 × 3.14 × 5 = 31.4 cm.

Tip

Diameter is twice the radius.

Practise it

• Worksheets: Circles, circumference and area (Grade 7)
• Online maths practice

Quick check: try these

Work each one out on paper, then tap the question to see the answer.

1. Area of a circle with radius 8 cm (use 3.14):

   Answer: 200.96

2. Area of a circle with radius 3 cm (use 3.14):

   Answer: 28.26

3. Area of a circle with radius 5 cm (use 3.14):

   Answer: 78.5

4. Circumference of a circle with radius 1 cm (use 3.14):

   Answer: 6.28

Learn it in depth

Circumference is part of Circles: Area and Circumference for Class 7: notes, formulas, solved examples with every step, common mistakes and ten practice questions with answers. Want a teacher to go through it with you? See Class 7 maths tuition.

Related words

Area, Perimeter