👁️ FOV Calculator
Enter a horizontal FOV and convert it between aspect ratios so the game feels the same on any monitor.
Equivalent FOV at 16:9
106.3°
Hor+ · same vertical FOV, matched feel
How the fov calculator works
Field of view set as a single number means different things on different aspect ratios, because most games scale FOV horizontally (Hor+). To keep the same vertical view, and therefore the same feel, when you change monitors, you recompute the horizontal FOV. This calculator converts using vFOV = 2·atan(tan(hFOV/2) ÷ aspect) and back out at the new aspect, so a 90° FOV on 4:3 becomes the matching wider number on 16:9 or 21:9. It computes instantly in your browser.
Hor+ (horizontal-plus) is the common scaling where a wider monitor shows more at the sides while keeping the same vertical view, which is what this tool matches. Some older games use Vert- scaling, which crops instead, there, a wider monitor shows less vertically. Knowing which your game uses tells you whether an ultrawide helps or hurts your view.
Frequently asked questions
How do I convert FOV between aspect ratios?
Keep the vertical FOV constant and recompute horizontal for the new aspect: vFOV = 2·atan(tan(hFOV/2) ÷ aspect), then the new hFOV = 2·atan(tan(vFOV/2) × newAspect). This tool does it, so a 4:3 FOV becomes its matching 16:9 or 21:9 value.
What is Hor+ and Vert- FOV scaling?
Hor+ (horizontal-plus) widens your view at the sides on wider monitors while keeping the vertical view, which most modern games use. Vert- crops the top and bottom instead, so an ultrawide shows less vertically. This tool matches Hor+.
What FOV should I use on an ultrawide monitor?
Set the FOV that gives you the vertical view you like, then this converter shows the matching horizontal number on 21:9 or 32:9, so your aim and sense of space stay consistent with a 16:9 setup.
Why does my FOV feel different on a new monitor?
Because the same FOV number produces a different vertical view at a different aspect ratio. Converting it (keeping vertical FOV constant) restores the familiar feel; this tool gives you that converted value.
Is anything uploaded?
No. The conversion runs in your browser.