What is the difference between horizontal, vertical, and diagonal FOV?

Horizontal FOV measures the angle from the left to the right edge of your screen. Vertical FOV measures from top to bottom. Diagonal FOV measures corner to corner. They are all related by your screen's aspect ratio — changing one changes all three.

What does Hor+ (horizontal plus) scaling mean?

Hor+ is the most common scaling method in PC games. As your aspect ratio gets wider (e.g. from 4:3 to 16:9), your horizontal FOV increases while your vertical FOV stays constant. Widescreen players see more of the scene without distortion.

What does Vert- (vertical minus) scaling mean?

Vert- keeps the horizontal FOV fixed and shrinks the vertical FOV as the aspect ratio widens. Widescreen players lose part of the top and bottom of the image. This is less common and considered inferior for ultrawide monitors.

Which FOV type should I use — 90 horizontal or 90 vertical?

It depends on your game engine. Unreal Engine, Unity, and most modern titles use vertical FOV internally. Quake-derived engines and many shooters use horizontal FOV. Always check your game's documentation. A 90 horizontal FOV on 16:9 equals approximately 59 vertical FOV.

What FOV is recommended for competitive play?

Most competitive FPS players prefer 90–110 horizontal FOV on a 16:9 display. Lower values (70–85) are common in sniper-heavy or slow-paced games. Going above 120 can cause fish-eye distortion that makes aiming harder.

Does FOV affect performance?

Yes. A wider FOV renders more of the scene, which increases GPU load. On lower-end hardware, dropping from 120 to 90 horizontal FOV can meaningfully improve frame rates, especially in dense environments.

FOV Game Calculator

Name: FOV Game Calculator
Availability: InStock
Author: Nham Vu

Convert field of view between horizontal, vertical, and diagonal for any screen aspect ratio and game engine.

Known FOV Input Type

Aspect Ratio

Ratio: 1.778

FOV Scaling

Hor+ adds horizontal view on widescreen. Vert- crops vertical view. Anamorphic is used by some older engines.

Quick Presets

Horizontal FOV

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degrees

Vertical FOV

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degrees

Diagonal FOV

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degrees

Your FOV Across Common Aspect Ratios

Based on your input using Hor+ scaling

Aspect Ratio	Horizontal	Vertical	Diagonal
Enter an FOV above to see comparisons.

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Summary

Convert field of view between horizontal, vertical, and diagonal for any screen aspect ratio and game engine.

How it works

Enter your known FOV value (horizontal, vertical, or diagonal).
Select whether that value is horizontal, vertical, or diagonal.
Choose your screen aspect ratio (16:9, 21:9, 4:3, or custom width/height).
Select the FOV scaling method your game uses (Hor+, Vert-, or Anamorphic).
The calculator instantly outputs all three FOV types in degrees.
Copy the value you need for any target game engine.

Use cases

Match your FOV feel when switching from a 16:9 monitor to an ultrawide 21:9 display.
Convert a vertical FOV (used in Source engine games) to horizontal FOV for Unreal Engine titles.
Find the equivalent diagonal FOV when a game only accepts that input type.
Verify that your 4:3 stretched FOV matches your 16:9 widescreen setup.
Calculate the correct horizontal FOV for custom or non-standard aspect ratios.
Understand how Hor+ and Vert- scaling affect your field of view.
Replicate a specific viewing angle across different game engines.
Convert a friend's recommended FOV setting to your own screen aspect ratio.

Frequently Asked Questions

Last updated: 2026-06-11 · Reviewed by Nham Vu