FOV Explained: Horizontal vs Vertical & Aspect Ratios

Two players can both be "on 103 FOV" and be seeing meaningfully different amounts of the world. FOV is an angle, but which angle — across the screen, up the screen, or corner to corner — is a choice each game makes, and the shape of your monitor changes the answer again. That is the whole reason FOV numbers travel badly between games.

What is the difference between horizontal and vertical FOV?

Horizontal FOV is the angle across the width of your screen, vertical FOV the angle up its height, and diagonal FOV corner to corner. They describe the same view, so any one of them implies the other two once you know the aspect ratio — which is exactly what the converter does.

On a 16:9 monitor, 103° horizontal is the same view as 70.5° vertical, and 110.5° corner to corner. Quote any of those three numbers and you have described one identical camera; quote one without saying which axis it is, and you have described nothing.

This is where cross-game comparison usually goes wrong. Two games can both show "103" and mean different angles, and a game that measures horizontally on a 4:3 base — the convention Source-engine games and their descendants use — will show a different number again from one that measures on 16:9. Check the axis before you copy a figure across.

Why does the same FOV look different on an ultrawide?

Because most games hold the vertical angle fixed and let the horizontal grow with the screen — the behaviour usually called Hor+. Widen the monitor and you gain view at the sides without losing any above or below. The table shows one setting, 103° horizontal on 16:9, expressed as the horizontal angle you would actually get on other shapes if the vertical is held constant.

That is a 53° spread across the same nominal setting. It is also why 4:3 players are not "seeing less" in the way people assume — they lose width, not height, and the trade is that everything left on screen is proportionally larger.

Does FOV change your sensitivity or cm/360?

No. cm/360 depends on your DPI, your in-game sensitivity and the game's yaw constant. FOV appears in none of those. Move your mouse 30 cm at 70 FOV and at 110 FOV and the camera turns through exactly the same angle both times.

What does change is how that rotation reads. A wide FOV squeezes more world into the same pixels, so a target crosses the screen in less mouse movement and the whole game feels twitchier. Plenty of players respond by nudging sensitivity down after raising FOV. That is a legitimate preference — just be clear that you are compensating for a visual change, not correcting a mechanical one, and change one variable at a time.

What FOV should you actually use?

• Higher FOV shows more of the world and warns you about flanks earlier — the main competitive argument for maxing it.
• Higher FOV also makes distant targets smaller, which costs you at range. This is the honest trade, and it is why not every pro maxes the slider.
• Motion sickness is real and asymmetric: low FOV triggers it in some people, very high FOV in others. Whichever way it hits you, that consideration outranks any competitive argument.
• Wider FOV renders more geometry, so it can cost frames on a GPU-limited setup. Check your own numbers rather than assuming.
• Whatever you pick, keep it. FOV is part of the muscle memory you build around distances and target size.

There is no correct answer here and anyone selling you one is guessing. The genuinely useful rule is the boring one: choose it once, on comfort, and stop touching it.

How do I match my FOV when changing monitor or game?

Put your current FOV into the converter, say which axis the game measures and which aspect ratio you are on, and read off the equivalent for the target. Moving from 16:9 to an ultrawide, hold the vertical angle constant — that keeps target size identical and simply hands you more peripheral view, which is what you bought the monitor for.