Game FOV calculator
Games describe field of view in different ways: some give the horizontal angle at 4:3, others the vertical angle, others the horizontal angle of your actual screen. Enter the FOV you know and the calculator gives the vertical angle and the horizontal angle on another aspect ratio.
Runs in your browser: nothing you enter is sent anywhere.
How to use
- Type the FOV value from the game or from a settings guide.
- Say whether it is horizontal or vertical, and on which aspect ratio it is measured — many games state their horizontal FOV at 4:3.
- Pick the aspect ratio of your screen under Convert to aspect ratio.
- Read the horizontal FOV on the target screen and the vertical FOV.
For a screen with aspect ratio a = width ÷ height:
- vertical = 2 × atan(tan(horizontal ÷ 2) ÷ a)
- horizontal = 2 × atan(tan(vertical ÷ 2) × a)
The angles are not proportional to the width: doubling the screen width does not double the angle, which is why a simple ratio gives wrong results.
Example
A game sets FOV 90 as the horizontal angle at 4:3. The vertical FOV is 2 × atan(tan 45° ÷ 1.333) = 2 × atan 0.75 = 73.74°. On a 16:9 monitor the game shows 2 × atan(0.75 × 1.778) = 2 × atan 1.333 = 106.26° horizontally.
Tips
- To match the view between two games, enter each game’s setting and compare the vertical FOV.
- A very wide horizontal FOV on a 32:9 screen stretches objects at the edges; that is normal for a flat projection.
- For camera lenses rather than games, use the lens field of view calculator.
Frequently asked questions
What is the difference between horizontal and vertical FOV?
Horizontal FOV is the angle you see from the left edge of the screen to the right edge, vertical FOV from top to bottom. On a wide screen the horizontal angle is much larger: 73.74° vertical is 90° horizontal at 4:3 but 106.26° at 16:9.
Why does the same FOV look different in two games?
Because a slider set to 90 can mean 90° horizontal at 4:3, 90° horizontal on your screen, or 90° vertical. Convert both games to the vertical FOV: when the vertical angles match, the view matches.
What is Hor+ scaling?
Most modern games keep the vertical field of view fixed and widen the horizontal one on wider screens, so an ultrawide shows more at the sides instead of cutting the top and bottom. The calculator uses this rule: vertical FOV stays the same, horizontal = 2 × atan(tan(vertical ÷ 2) × width ÷ height).
Which 21:9 should I choose?
21:9 is a marketing name. 2560×1080 and 5120×2160 screens are 64:27 (2.37), 3440×1440 screens are 43:18 (2.39). The difference is under half a degree for typical FOVs, but both are listed.