The calculation for a 16:9 video resolution aspect ratio, given the width or height value.

Read up about the 16:9 aspect ratio.

Calculating width

To calculate the 16:9 width for your height value:

(height * 16) / 9

It is height multiplied by 16 then divided by 9.

(1080 * 16) / 9 = 1920

1920 x 1080

(1123 * 16) / 9 = 1996.4444444444

This is not a round number making it unsuitable.

Calculating height

Now calculating the 16:9 height for a width value:

(width / 16) * 9

The difference here is just changing the multiplication and division.