Circumference to Radius Calculator

Find a circle's radius and diameter from its circumference.

Radius 5

Diameter 10

Area 78.54

Formula: radius = circumference ÷ (2π)

Step-by-step with your numbers:

1. Values used:

2. Circumference = 31.416

4. Radius = 5

5. Diameter = 10

6. Area = 78.54

Did we solve your problem today?

Work backwards from a circle's circumference to its radius, diameter and area.

The math behind it

Since circumference = 2πr, the radius is circumference ÷ (2π).

Circumference 31.42 → radius 5, diameter 10.

How do I get the diameter directly?

diameter = circumference ÷ π.