Question: Is it possible to measure the physical distance on my monitor using Screen Calipers?

Answer: The Screen Calipers cannot actually measure the physical distance on your monitor automatically, it’s simply not available in the software. If you think about it you could have a projector hooked up to your computer and the screen could be shown at any size on a wall, and obviously in this situation the software could not “see” the physical distance.

Therefore the Calipers needs to be calibrated if you want to measure the exact physical distance on your monitor.
• To do this extend the Calipers to a very wide distance, say 11”s and hold up a ruler so you know that the distance is accurate.

• Set the Calipers to use “Pixels” as it’s measurement unit. In the custom units box create a new unit called “My Monitor”.

• Type in the number of pixels currently shown in the “Number of Pixels” box, in the example below this is 1006, but yours will be different.

• In the “Length in Units” box type in 11 for your eleven inches measured.

• Click OK and you’ll now be measuring your exact screen size.

Please refer to the this link to see the Calibration window with the new 'My Monitor' measurement unit defined.