Use this free circumference calculator to find the area, circumference and diameter of a circle.
The circumference of a circle is the distance around the boundary of the circle. It is the same as calculating the perimeter of any polygon such as triangle, square, and rectangle.
How to calculate the circumference of a circle? The circumference of a circle is calculated using the formula: 2 x π x radius, where π is a mathematical constant, equal to about 3.14159.
Keep reading for everything you need to know about how to figure out the circumference of a circle using either the diameter or the radius. We've even got a circumference calculator to make things easy. Use the formula C = πd to find the circumference if you know the diameter.
The circumference of a circle is the distance around it, but if, as in many elementary treatments, distance is defined in terms of straight lines, this cannot be used as a definition.
This calculator computes the values of typical circle parameters such as radius, diameter, circumference, and area, using various common units of measurement.
You sometimes see the word 'circumference' to mean the curved line that goes around the circle. Other times it means the length of that line, as in "the circumference is 2.11cm".
The formula for circumference is based on the constant π (pi), which is an irrational number approximately equal to 3.14159. π is the ratio of the circumference to the diameter of any circle.
Use our simple calculator to find the circumference of a circle. Learn how to solve circumference problems with our step-by-step guide.