Calculate the Area of a Circle
This will calculate the area of a circle based on its diameter. Confused as to what diameter means? Scroll down for a diagram.
Area of a 10′6″ diameter circle
results may be rounded
Area of a Circle Formula
The area of a circle is pi times the square of its radius. The radius is half the diameter.
Area = π * (Diameter / 2)2
Diameter of a Circle
The diameter of a circle is the distance from one edge to the other, passing through the center. It is twice the radius.