What is circle?

Circle is a two dimensional geometric shape which is a curved line around a central point. In simple terms circle is the boundary of a disk.

How circumference is being calculated?

Formula for the circumference of a circle is $C=2\mathrm{\pi r}$, where π is ~ 3.14159 and r is the radius. Radius is a positive number.

You can use the tool above to calculate both area and circumference of a circle. Put the radius into the input field and choose unit of length. Circumference and circle will be calculated automatically.

How area is being calculated?

Formula for the area of a circle is $\mathrm{A}={\mathrm{\pi r}}^2$, where π is ~ 3.14159 and r is the radius.