Display Calculators
Monitor distance and field of view.
Enter the monitor diagonal, the aspect ratio and how far your eyes are from the screen to get the horizontal and vertical field of view, and the distance that gives a 30 or 40 degree view. Runs in your browser; nothing is sent or stored.
Inputs
Result
Fill the form and press Calculate.
Worked example
A 27 inch 16:9 monitor is 23.53 in x 13.24 in. From 28 in away it fills 2 x atan(23.53 / (2 x 28)) = 45.6 degrees horizontally and 26.6 degrees vertically. A 30 degree view would be at 43.9 in and a 40 degree view at 32.3 in. 28 in is inside the 20 to 40 in range OSHA calls the preferred viewing distance.
How it works
Field of view = 2 x atan(size / (2 x distance)), using the screen width for the horizontal angle and the height for the vertical one. The 30 and 40 degree distances are the viewing angles in the Optimum HDTV viewing distance - Wikipedia article, which describes them for TVs; they are not desk-ergonomics rules.
For comfort at a computer, OSHA says that generally the preferred viewing distance is between 20 and 40 inches (50 and 100 cm) from the eye to the front surface of the screen, and that text size may need to be increased for smaller monitors. This calculator is geometry, not medical or ergonomic advice.
Sources: eTools : Computer Workstations - Workstation Components - Monitors | Occupational Safety and Health Administration; Optimum HDTV viewing distance - Wikipedia. Each opened 2026-10-08.
Planning guide only, not professional advice. Figures are estimates from the inputs you enter.
FAQ
How far should I sit from my monitor?
OSHA says the preferred viewing distance is generally 20 to 40 inches (50 to 100 cm) from the eye to the screen. Adjust for monitor size and your comfort; this is not medical advice.
How do I calculate monitor field of view?
FOV = 2 x atan(width / (2 x distance)). A 27 inch 16:9 monitor at 28 inches fills about 45.6 degrees horizontally.
Does a bigger monitor need more distance?
For the same field of view, yes: the distance scales with the screen width. A 27 inch monitor needs 32.3 in for a 40 degree view.
Is a 40 degree monitor view right for desk work?
The 40 degree figure is a TV immersion guide. For desk work, choose a distance where you can read all the text comfortably without moving your head a lot.