You start a new shooter and the world feels cramped, like you are looking through a letterbox. Or the opposite: everything looks stretched and you feel slightly sick after ten minutes. Both problems usually come from one setting with a confusing name: field of view, or FOV.
Field of view is how much of the game world fits on your screen at once, measured as an angle. A small angle is like zooming in: you see a narrow slice, and everything in it looks big. A large angle is like zooming out: you see more of the world around you, but each thing looks smaller, and things near the edges of the screen look stretched.
It is not the same as zoom when you aim down a scope. That is a temporary change to the same setting. Your normal FOV is the one you live with all the time.
A wider FOV shows you more of what is to your left and right without turning. In a shooter that means spotting a player at the edge of the screen earlier. In a racing game it means seeing the corner and the car beside you at once. Because you see more, your brain also reads your own movement as faster, which many players find more natural.
The cost is that the same picture is squeezed into the same screen. Things in the middle get smaller, and things near the edges are stretched sideways. Push the slider past 110 in the demo and the outer pillars look fat. Very high values can also cost some performance, because the game has to draw more of the world.
A narrow FOV is the opposite. Targets look large and easy to read, and some people find it calmer. But the view feels like a tunnel, and many people get a headache or feel motion sick because the world seems to rush at them.
Games quote FOV in two ways. Horizontal FOV measures the angle from the left edge of the screen to the right edge. Vertical FOV measures from top to bottom. The same view has a different number in each. On a normal 16:9 screen, a vertical FOV of 60° is about 91° horizontal. A game that says "60" and one that says "90" can therefore be showing almost the same picture.
It also changes with the shape of your screen. Keep the vertical FOV fixed and an ultrawide monitor shows you more at the sides, while a 4:3 screen shows less. So when you follow advice like "set it to 100", check which kind the game uses. Most settings menus do not say, but many guides for a game will.
There is no perfect value, only what feels right on your screen at your sitting distance. The closer you sit, the wider your FOV can be before things feel stretched. Someone on a laptop a short distance away often likes a higher number than someone on a TV across the room.
Start in the middle of what the game offers, play a few minutes, and nudge it. If the world feels like it rushes past you and you feel dizzy, try a higher value; if everything looks stretched at the edges, come back down. If you cannot see enemies approaching from the sides, go wider. Many console games fix the value or offer only a small range, and that is normal: they are tuned for a couch and a TV.
The number only means something together with your screen size and how far away you sit. A big TV across the room fills only a part of your own view, so a moderate FOV already looks natural there. A small monitor right in front of your face fills more of your view, so a higher FOV can look more realistic, because the picture matches what your eyes would see through a window that size. This is why two people can disagree about the "right" value and both be correct.
If you play on both a console and a PC, expect to land on different numbers. That is not a mistake in either setup. Treat the values you read online as a starting point for a quick test, not a rule you must follow.
Find the setting under Video, Graphics or Gameplay. Check whether it is horizontal or vertical. Change it in small steps, test in a familiar spot, and keep it only if it feels comfortable after a few minutes, not just in the first one. If the game slows down after you widen it, bring it back a little.