Real size formula

Have you ever asked yourself 'How do I preview a document in real size?'

The formula in the attachment allows you to calculate the zoom factor needed to preview a document in real size in your own monitor.

The variables are:

h - horizontal screen resolution (ex.: 1920 px)
v - vertical screen resolution (ex.: 1080 px)
d - monitor diagonal size in inches (ex.: 23")
r - document resolution (ex.: 300 dpi)

Using the values above you would get '32%'. This means a zoom factor of 32% is needed to preview a 300 dpi document in the real output size for a display with the above specs. The value is a constant so you just need to calculate once for each document resolution (r).

Replace the variables and get your result here: http://www.wolframalpha.com/input/?i=z+%3D+(100+sqrt(h%5E2%2Bv%5E2))%2F(d+r)