You loaded up a new game, looked around, and something felt wrong. The world seemed squashed, or the car felt like it was floating, or twenty minutes in you had a headache you could not explain. Nine times out of ten the culprit is field of view.
FOV is one of those settings people leave on default for years without realising it is quietly ruining their experience. This guide explains what FOV actually is, how to calculate the right number for your setup, and why the “correct” value depends on how far your face is from the screen. If you want the answer without the trigonometry, our FOV Calculator handles it instantly.
What Field of View Actually Means
Field of view is the angle of the world you can see at once, measured in degrees. A low FOV is like looking through a paper towel tube — zoomed in, narrow, distant. A high FOV is like standing in the room — wide, peripheral, close.
Here is the part most people miss: there is no universally correct FOV. The right number depends on your screen size and how far away you sit. A setting that feels perfect on a 24-inch monitor at arm’s length feels absurd on a TV across the room.
Horizontal, Vertical and Diagonal FOV
This is where most confusion starts. Three different games can all say “FOV: 90” and show you three different amounts of world, because they are measuring different axes.
Horizontal FOV (hFOV) — the angle across the width of the screen. Most first-person shooters use this.
Vertical FOV (vFOV) — the angle top to bottom. Source engine games and many sim titles use this.
Diagonal FOV — corner to corner. Less common, but it exists.
Why it matters: at 16:9, a 90° horizontal FOV is roughly a 59° vertical FOV. If you type 90 into a game expecting horizontal and it wants vertical, you get a fisheye lens. This single mix-up is behind most “why does this look so weird” complaints.
The Formula for Calculating FOV
The honest answer for a screen you sit in front of comes from simple trigonometry. Your eye, the centre of the screen, and the edge of the screen form a right triangle:
FOV = 2 × arctan( (screen width ÷ 2) ÷ viewing distance )
Worked example: a 24-inch 16:9 monitor is about 21 inches wide. You sit 24 inches away.
Half-width = 10.5 inches.
arctan(10.5 ÷ 24) = arctan(0.4375) = about 23.6°.
FOV = 2 × 23.6 = about 47° horizontal.
That is your true geometric FOV — the angle your eyes actually see. Set the game to this and the image is geometrically perfect, with zero distortion.
So Why Doesn’t Anyone Use the “Correct” FOV?
Because a geometrically perfect 47° in a shooter feels claustrophobic and gets you killed. You cannot see anyone flanking you.
This is the real trade-off nobody explains: geometric accuracy and competitive awareness pull in opposite directions. Most players compromise:
Competitive FPS — 90 to 106° horizontal. You accept edge distortion in exchange for seeing threats.
Single-player / cinematic — 70 to 90°. Closer to natural, more immersive.
Sim racing — use the calculated value. This is the one case where accuracy genuinely wins.
Sim Racing Is the Exception
In racing sims, a wrong FOV does not just look odd — it destroys your driving. Your brain judges braking points and corner entry by how fast the world scales toward you. Set the FOV too wide and everything appears further away and slower than it is, so you brake late and misjudge apexes for months without knowing why.
Calculate it properly, and something clicks: the car feels planted, distances read correctly, and your lap times drop. Most sim racers report the calculated FOV feels uncomfortably narrow for about two sessions, then they can never go back.
FOV for Cameras and Photography
Photographers deal with the same maths from the other side. Instead of screen width and viewing distance, you have sensor size and focal length:
FOV = 2 × arctan( sensor dimension ÷ (2 × focal length) )
A 50mm lens on a full-frame sensor (36mm wide) gives about a 39.6° horizontal field of view — which is roughly why 50mm is called a “normal” lens. It approximates what your eye considers natural.
Crop sensors change everything. The same 50mm lens on an APS-C body behaves like a 75mm on full frame, narrowing your view considerably. This is why a lens that felt perfect on one camera feels too tight on another.
Common FOV Mistakes
Copying a streamer’s setting. Their FOV is right for their monitor and their seating distance. Yours are different, so the number is meaningless to you.
Ignoring ultrawide. On a 21:9 or 32:9 display, a game applying vertical FOV gives you extra width for free; a game applying horizontal FOV squeezes your vertical view instead. Know which your game uses before you complain.
Cranking it to maximum. Very high FOV stretches the edges badly and shrinks distant enemies into a few pixels — harder to see, not easier.
Forgetting motion sickness is real. If you get queasy in games, FOV that is too low is the usual cause. Your inner ear expects peripheral motion that the narrow view does not deliver, and the mismatch makes you ill. Raising FOV fixes it for many people.
Get Your Number in Seconds
Measure your screen width and how far your eyes sit from it, put both into our free FOV Calculator, and it returns your true horizontal and vertical field of view — plus conversions for sim racing, gaming, photography and astronomy. Free, no sign-up.
Frequently Asked Questions
How do you calculate field of view?
Use FOV = 2 × arctan((screen width ÷ 2) ÷ viewing distance). Measure the visible width of your display and the distance from your eyes to the screen, both in the same units. The result is your true horizontal field of view in degrees.
What is a good FOV for gaming?
For competitive first-person shooters, 90–106° horizontal is the common range. For single-player and cinematic games, 70–90° feels more natural. For sim racing, use your geometrically calculated value rather than a preference.
How do I convert horizontal FOV to vertical FOV?
The conversion depends on your aspect ratio: vFOV = 2 × arctan(tan(hFOV ÷ 2) ÷ aspect ratio). At 16:9, a 90° horizontal FOV works out to roughly 59° vertical.
Why does a low FOV make me feel sick?
Your inner ear expects the peripheral motion cues you would get in real life. A narrow FOV removes them while the screen still shows movement, and that mismatch triggers motion sickness. Raising FOV resolves it for most people.
What FOV should I use for sim racing?
The calculated one, based on your screen width and seating distance — no compromise. It usually feels too narrow at first, but it is what makes braking points and corner distances read correctly, and it is the single biggest free improvement to your lap times.
Does FOV affect performance?
Slightly. A wider FOV renders more of the scene, so more objects are drawn each frame. On modern hardware the cost is usually small, but on a heavily loaded system it is measurable.