Click to reload page with unique web address for bookmarking or sharing current settings

## Related Tools

- Calculate diameter of circle from area
- Convert an area to different units
- Length and distance converter
- Cylinder volume calculator

## User Guide

This tool will calculate the area of a circle from the diameter, and will convert different measurement units for diameter and area.

### Formula

The formula used to calculate circle area is:

A = π x (ø/ 2)^{2}

#### Symbols

- A = Circle area
- π = Pi = 3.14159…
- ø = Circle diameter

### Diameter of Circle

Enter the diameter or two times the radius of a circle.

### Area of Circle

This is the area contained within a circle with the specified diameter.