The **Area of a Circle Calculator** will straight away calculate the area of a circle when you just input the circle’s radius. The actual radius of a circle is the length from the middle of the circle to its outer side in a straight line. The radius is equivalent to half of a circle’s diameter (the diameter of a circle is the distance from one edge of a circle to the opposite edge in a straight line). It means that discover possibly the actual diameter of a circle or go with the radius of a circle perhaps you can simply divide the diameter by two to find the radius or multiply the radius times two to find the diameter.

Just Enter the radius of the circle below and hit the calculate button to calculate the area of the circle.

## How to Calculate the Area of a Circle

r = radius

C = circumference

A = area

π = pi = 3.14159

√ = square root

## Area of A Circle Formula

**Radius and Diameter:**

r = d/2

**Area of a circle:**

A = πr

^{2}= πd^{2}/4

**Circumference of a circle:**

C = 2πr = πd

If r = 3 cm for instance,

area = 3.14 × 3^{2} = 3.14 ×9 = 28.27 cm^{2}

Use this free online area of a circle calculator to find the area for any circle.