# Aperture Area Calculator

Enter the focal length, aperture diameter, and the f-number into the calculator to determine the aperture area.

## Aperture Area Formula

The following formula is used to calculate the aperture area.

A = π (D / 2)^2 = π (n/ (2 * f))^2,

• Where D is the aperture diameter (mm)
• n is the focal length (mm)
• f is the f-number,
• A is the aperture area (mm^2)

An aperture is a hole, and as a results the aperture area is simply a measure of the area of that hole. It’s a characteristic that effects how much light can pass through an object. For the human eye, this aperture is the pupil, which can expand or contract depending on how much light is needed to see.