# Calculate the Diameter of a Circle, from Its Area (or Vice Versa)

A change to any field will make the script recalculate. All of them will change the calculated diameter, EXCEPT for the numerical value of the diameter, which will recalculate the area.

Calculate the diameter of a circle, from its area

The form calculator requires JavaScript. If JavaScript is not working on your browser, or in case you are simply curious, here is the procedure for calculating the diameter of a circle from its area. For an example, we have an area of 303,000 square meters.

1. Divide the area (in square units) by Pi (approximately 3.14159).
Example: 303,000/3.14159 = 96,447.98
2. Take the square root of the result (Example: 310.56). This is the radius.
3. Now double the radius to get the diameter (Example: 621.12 meters).

The procedure is reversed to calculate the area of a circle from its diameter. Starting with a diameter of 150 meters:

1. Divide the diameter by 2 to get the radius (Example: 150/2 = 75)
2. Square the radius (Example: 75 × 75 = 5,625)
3. Multiply the result by Pi to get the area (Example: 5,625 × 3.14159 = approximately 17,671 square meters)