A horizontal FOV of 90° at 4:3 equals a horizontal FOV of about 106.3° at 16:9, because the vertical FOV of 73.7° stays the same. The conversion is hFOV₂ = 2·atan(tan(vFOV/2) × aspect₂), with vFOV = 2·atan(tan(hFOV/2) ÷ aspect₁).
What is FOV in games?
Field of view is how much of the 3D world the game camera shows, measured in degrees. Different games quote different FOVs: some use horizontal FOV, some vertical, and a few diagonal. The same number looks very different on 4:3 and 21:9 screens, which is why players search for a way to convert between them. Console games typically use 60° to 90° horizontal, and many PC shooters let you pick between 90° and 120°.
How the conversion works
The vertical and horizontal FOV are linked by the aspect ratio through the tangent: tan(hFOV ÷ 2) = tan(vFOV ÷ 2) × aspect. Most modern games are “Hor+”, meaning the vertical FOV stays fixed and the horizontal FOV grows when the screen is wider. Under that rule, a 90° horizontal FOV at 4:3 becomes 106° at 16:9 and 121° at 21:9. A few older titles use “Vert−” scaling instead, keeping horizontal constant and cutting off the top and bottom on wide screens, which you can emulate by choosing the same horizontal value at both ratios.
| hFOV at 4:3 | 16:10 | 16:9 | 21:9 |
|---|---|---|---|
| 70° | 80° | 86° | 102° |
| 90° | 100° | 106° | 121° |
| 100° | 110° | 116° | 129° |
Which FOV should you use?
- Realism: the “correct” FOV is the one that matches the real angle your screen takes up. A 60 cm wide monitor viewed from 70 cm is about 46° wide in reality. The optional fields calculate this. Games usually use more, so more of the world is visible.
- Competitive play: a wider FOV shows more of your surroundings but makes distant targets smaller.
- Comfort: very high FOV causes edge distortion, and low FOV with fast motion can feel claustrophobic. Many people prefer something around 90° to 100° horizontal on a 16:9 monitor.
Screen geometry
The same triangle maths behind FOV is used in the Pythagoras calculator, where the monitor diagonal follows from width and height. For Minecraft players, there is also the Nether coordinates calculator.
How to use this calculator
- Enter the FOV your game uses and say whether it is horizontal or vertical.
- Select the aspect ratio it applies to and the aspect ratio you want to convert to.
- Read the converted horizontal FOV, the vertical FOV and the diagonal.
- Optionally add monitor width and eye distance to see the real FOV your eyes get.
Key figures at a glance
| Link | tan(h/2) = tan(v/2) × aspect |
|---|---|
| Hor+ | Vertical FOV fixed, horizontal grows |
| 90° at 4:3 | ≈ 106° at 16:9, ≈ 121° at 21:9 |
| Real FOV | 2 × atan(width ÷ 2 ÷ distance) |
Frequently asked questions
Compute the vertical FOV from the horizontal one, then use the new aspect ratio to get the 16:9 horizontal FOV. 90° at 4:3 becomes about 106° at 16:9.
A scaling method where the vertical FOV is fixed and the horizontal FOV expands for wider aspect ratios.
It shows more of the scene but makes objects look smaller and can distort the edges. It is a preference and a trade-off.
Divide half the screen width by the viewing distance, take the arctangent and double it.
Minecraft’s FOV slider is vertical.