FOV Converter for FPS Games
(Horizontal & Vertical FOV Calculator)
Convert field of view between CS2, Valorant, Apex Legends, Overwatch 2, Rainbow Six Siege, Call of Duty, Fortnite and PUBG — with real horizontal and vertical FOV trigonometry across 4:3, 16:9, 16:10 and 21:9 aspect ratios.
# Understanding FOV Scaling: Horizontal (16:9) vs Vertical FOV
Horizontal FOV is the angle of the world visible left to right; vertical FOV is the angle visible top to bottom. On any screen, these two are locked together by your aspect ratio, following the formula:
tan(hFOV ÷ 2) = aspect ratio × tan(vFOV ÷ 2)
Different game engines expose the FOV slider using different bases, which is the real reason the "same number" feels completely different between titles:
- Hor+ (horizontal-fixed): the slider value directly is your horizontal FOV, unaffected by aspect ratio. Valorant, Overwatch 2, Call of Duty and Fortnite are commonly documented to work this way.
- Vert- (vertical-fixed, 4:3 base): the slider value represents your FOV as if you were still on a 4:3 screen; the engine keeps vertical FOV constant and widens horizontal FOV as your real aspect ratio gets wider. CS2 and Apex Legends are commonly documented to work this way, inherited from the Source engine's legacy FOV system.
- Vertical-direct: the slider value is your vertical FOV directly. Rainbow Six Siege is a notable example of this less common approach.
This calculator converts by holding vertical FOV constant between your source and target game, since vFOV stays more stable across a player's actual eye-to-screen viewing geometry than horizontal FOV does.
# Native FOV Measurement Standards by Game (CS2, Valorant, Apex, R6)
The table below summarizes each game's commonly documented FOV measurement type, native slider range, and typical default. Treat exact min/max/default figures as reference points — they can shift slightly between patches, so double-check your in-game settings menu.
| Game | Measurement type | Slider range | Typical default |
|---|
Ranges and defaults are compiled from commonly cited community references and may vary slightly by patch, platform or competitive ruleset. This tool's math (the hFOV ↔ vFOV trigonometric relationship) is exact; the per-game "measurement type" classification is a widely used characterization, not an official spec published by every developer.
# Frequently Asked Questions
Horizontal FOV measures how many degrees of the world you can see left to right, while vertical FOV measures how many degrees you see top to bottom. The two are linked by your aspect ratio: on a wider screen, the same vertical FOV produces a larger horizontal FOV, which is why converting FOV between games with different aspect ratios requires more than just copying the number.
Games like CS2 traditionally store your FOV setting as if you were playing at a 4:3 aspect ratio, then expand your actual horizontal FOV outward to fill a wider 16:9 screen while keeping vertical FOV constant. To convert, first calculate the constant vertical FOV from your 4:3 value, then recompute the horizontal FOV using your real 16:9 aspect ratio — this calculator does that automatically when you select CS2 as your source game and 16:9 as your aspect ratio.
Rainbow Six Siege's FOV slider is commonly documented as directly setting vertical FOV rather than horizontal FOV, which is less common among FPS titles. This means its horizontal FOV at any given aspect ratio must be derived from that vertical value, which is exactly what this converter does when Rainbow Six Siege is selected as the source or target game.
There is no single best FOV, since it depends on personal preference, monitor distance, and the specific game's engine and default competitive settings. Most competitive players at 16:9 tend to sit in a horizontal FOV range of roughly 90 to 110 degrees, balancing wider peripheral awareness against the slight distortion and smaller-looking target models that come with an ultra-wide FOV setting.
Matching vertical FOV between games is generally the most reliable way to keep a consistent visual feel, since it stays stable regardless of each game's internal horizontal scaling behavior. This calculator holds vertical FOV constant when converting your source game's setting into the equivalent value for your target game.