FOV Converter

FOV value, degrees

What kind of FOV

Aspect ratio: width

Aspect ratio: height

Result

Horizontal at your ratio, °106.26
Horizontal at 4:3, °90
Vertical, °73.74
Aspect ratio16:9
As a decimal1.7778
What mattersSource-engine games set the horizontal angle at 4:3 and widen it on wider screens, leaving the vertical angle untouched.

Three ways to name the same view

Converts a field of view between horizontal at 4:3, horizontal at your aspect ratio, and vertical.

Games measure field of view differently, so 90 in one game can mean something quite different in another. Source sets the horizontal angle at 4:3, many modern engines set the vertical one, and some set the horizontal angle at the current screen ratio.

The constant is the vertical angle: moving to a wider monitor normally widens the picture at the sides without changing what is visible above and below. Every conversion here routes through it.

What this calculator shows

The same view in all three measurement systems
How the horizontal angle changes at your aspect ratio
The aspect ratio as a fraction and as a decimal

What to keep in mind

The calculation assumes horizontal expansion on a wider screen, which is how most shooters behave.
Some games crop the top and bottom instead; there the vertical angle is not preserved and the conversion does not apply.

FAQs

How does horizontal FOV differ from vertical?

Horizontal measures the angle across the screen's width, vertical across its height. Moving to a wider monitor grows the first and leaves the second alone.

What FOV is best for shooters?

A wider angle shows more at the edges but shrinks targets in the centre. Most settle between 90 and 106 horizontal at 16:9; beyond that, accuracy and distance judgement start to suffer.

Why do ultrawide monitors show more?

Because the game widens the picture at the sides while keeping the vertical angle. On 21:9 that is a real advantage in games where such expansion is allowed.

Does FOV affect mouse sensitivity?

On Source-engine games, no — rotation per count is constant. On some other engines turn speed is tied to the angle, and changing FOV changes how the sensitivity feels.

Worked example

The classic ninety

Input: FOV 90 horizontal at 4:3, screen 16:9

Output: 106.26° horizontal and 73.74° vertical

Note: 106.26 is a number familiar to anyone who has edited a config: that is what a widescreen monitor shows at the standard Source ninety. The vertical angle does not move at all.

Useful links

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FOV Converter

Result

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