How to Convert Field of View Between Aspect Ratios

Field of view, or FOV, is how much of a scene you can see at once, measured as an angle. A wider FOV shows more of the world but makes distant objects look smaller, while a narrower FOV zooms in and feels more focused. Games, cameras, and VR headsets all express this as horizontal or vertical degrees.

The catch is that a game or app may define FOV horizontally while another defines it vertically, and the two are linked by the aspect ratio of your display. Convert incorrectly and the view can feel stretched, cramped, or dizzying, which is why matching FOV across setups requires the right math.

Horizontal and vertical FOV are related through the aspect ratio using the formula vFOV equals 2 times the arctangent of the tangent of half the hFOV divided by the aspect ratio. The tangent and arctangent appear because FOV is an angle, not a simple linear measure, so you cannot just multiply by the ratio.

The practical takeaway is that a wider aspect ratio produces a larger horizontal FOV for the same vertical FOV. This is why an ultrawide monitor shows more to the sides than a standard 16 by 9 screen when the vertical view is held constant. Fixing the vertical FOV keeps the sense of scale steady as you change screen width.

The calculator applies the trigonometry for you, so you only supply the known angle and the aspect ratio and read the converted value.

Competitive players often widen FOV for better peripheral awareness, while cinematic players prefer a narrower view. When you switch monitors or move to an ultrawide, converting your FOV keeps the feel consistent instead of forcing you to relearn distances and aim.

The same math helps match a camera lens to a target framing or set a comfortable VR view. Whenever an app asks for one axis but you know the other, this conversion keeps proportions correct so the world looks natural rather than distorted.