Optimal Field of View (FOV) Calculator

How to calculate Field of View (FOV) calculator?

Field of View (FOV) is the angular extent of the scene visible from your viewing position. It is derived from the monitor's effective width or height and your viewing distance.

Use the monitor's effective linear size (in inches) and the viewing distance (in inches): horizontal_fov_deg = 2 * atan((monitor_width_inches / 2) / viewing_distance_inches) * 180 / π

Using the Field of View (FOV) calculator calculator: an example

Example values: 27" diagonal, 16:9 aspect ratio (effective width ≈ 23.55 in), viewing distance 30 in.

Step-by-step calculation:

1. Calculate effective monitor width: for 27" 16:9, width ≈ 27 × (16 / √(16²+9²)) ≈ 23.55 in.
2. Compute horizontal FOV: horizontal_fov = 2 × atan((23.55 / 2) / 30) ≈ 42.8°.
3. Compute effective height: height ≈ 27 × (9 / √(16²+9²)) ≈ 13.24 in, then vertical_fov = 2 × atan((13.24 / 2) / 30) ≈ 24.9°.
4. Interpretation: a 27" 16:9 monitor at 30 in gives roughly 42.8° horizontal and 24.9° vertical FOV.

Frequently Asked Questions

Does aspect ratio directly change FOV?

Aspect ratio itself does not change viewing distance; it changes effective width and height for a given diagonal, which in turn affects horizontal and vertical FOV.

Should I use diagonal or width in the formula?

Use the monitor's effective width for horizontal FOV and effective height for vertical FOV; convert diagonal and aspect ratio to get those linear sizes first.

How does viewing distance affect immersion?

Closer viewing distance increases angular FOV and typically improves immersion, but very large FOVs can cause discomfort; adjust distance to balance immersion and comfort.