Arma 3 FOV Calculator

Calculate the Vertical Field of View (VFOV) and fovTop/fovLeft values for Arma 3 based on your monitor’s aspect ratio and desired Horizontal FOV (HFOV).

FOV Calculator

What is an Arma 3 FOV Calculator?

An Arma 3 FOV calculator is a tool designed to help players of the military simulation game Arma 3 determine the optimal Field of View (FOV) settings for their specific monitor setup and preference. In Arma 3, the FOV settings, particularly the `fovTop` and `fovLeft` values in the configuration file, directly influence how much of the game world is visible on screen, affecting both situational awareness and the perceived sense of speed and scale.

Unlike some games that use a simple Horizontal FOV (HFOV) slider, Arma 3’s FOV is often discussed in terms of Vertical FOV (VFOV) or the `fovTop` value, which is derived from it. The relationship between HFOV and VFOV depends on the monitor’s aspect ratio (e.g., 16:9, 21:9). This Arma 3 FOV calculator helps bridge that gap, allowing you to input a desired HFOV for your aspect ratio and get the corresponding VFOV and `fovTop` values.

Anyone who plays Arma 3 and wants to fine-tune their visual experience, especially those with non-standard aspect ratio monitors (like ultrawide 21:9 or super ultrawide 32:9), should use an Arma 3 FOV calculator. It ensures that the FOV is correctly adjusted for their screen, preventing distortion or an unnaturally narrow/wide view. A common misconception is that the in-game slider directly sets HFOV for all aspect ratios; it’s more complex, and using a calculator provides precise values.

Arma 3 FOV Calculator Formula and Mathematical Explanation

The core of the Arma 3 FOV calculator revolves around the relationship between Horizontal FOV (HFOV), Vertical FOV (VFOV), and the Aspect Ratio (AR) of the display.

1. Aspect Ratio (AR): This is the ratio of the monitor’s width to its height (e.g., 16/9, 21/9).

2. Relationship: The tangent of half the HFOV divided by the tangent of half the VFOV equals the aspect ratio:

tan(HFOV / 2) / tan(VFOV / 2) = AR

3. Calculating VFOV from HFOV: If you know your desired HFOV and your AR, you can find VFOV:

tan(VFOV / 2) = tan(HFOV / 2) / AR

VFOV = 2 * atan(tan(HFOV / 2) / AR) (Result in radians, convert to degrees by multiplying by 180/π)

4. Calculating HFOV from VFOV: Conversely:

HFOV = 2 * atan(tan(VFOV / 2) * AR)

5. fovTop and fovLeft: Arma 3’s configuration files often use `fovTop` and `fovLeft`, which are related to the VFOV and HFOV:

fovTop = tan(VFOV / 2)

fovLeft = tan(HFOV / 2) = tan(VFOV / 2) * AR

Our Arma 3 FOV calculator primarily takes your desired HFOV for your AR and calculates the VFOV and `fovTop` value.

Variables Used in FOV Calculation

Variable	Meaning	Unit	Typical Range
HFOV	Horizontal Field of View	Degrees	60 – 120
VFOV	Vertical Field of View	Degrees	30 – 90
AR	Aspect Ratio (Width/Height)	Dimensionless	1.33 – 3.56
fovTop	Config value related to VFOV	Dimensionless	0.3 – 0.8
fovLeft	Config value related to HFOV	Dimensionless	0.5 – 1.5

Practical Examples (Real-World Use Cases)

Let’s see how the Arma 3 FOV calculator works in practice.

Example 1: Standard 16:9 Monitor

• Aspect Ratio Width: 16
• Aspect Ratio Height: 9
• Desired Horizontal FOV: 90 degrees

Using the Arma 3 FOV calculator, we find:

• Vertical FOV: ~58.99 degrees
• fovTop: ~0.5658
• This is a common setup, giving a good balance between awareness and target visibility on a standard widescreen monitor.

Example 2: Ultrawide 21:9 Monitor

• Aspect Ratio Width: 21
• Aspect Ratio Height: 9
• Desired Horizontal FOV: 103 degrees

Using the Arma 3 FOV calculator, we get:

• Vertical FOV: ~56.12 degrees
• fovTop: ~0.5330
• For an ultrawide, a higher HFOV like 103 is often preferred to take advantage of the extra width without excessive vertical cropping, but notice the VFOV is still relatively low compared to the HFOV.

How to Use This Arma 3 FOV Calculator

1. Enter Aspect Ratio: Input the width and height parts of your monitor’s aspect ratio (e.g., 16 and 9 for 16:9, 21 and 9 for 21:9).
2. Enter Desired HFOV: Input the Horizontal FOV in degrees you wish to achieve on your monitor.
3. View Results: The Arma 3 FOV calculator will instantly show the calculated Vertical FOV (degrees), fovTop, fovLeft, Diagonal FOV, and your exact Aspect Ratio.
4. Apply to Arma 3: The `fovTop` and `fovLeft` values can often be used to fine-tune settings in your `YourProfileName.Arma3Profile` file located in `Documents\Arma 3` or `Documents\Arma 3 – Other Profiles`. Look for `fovTop` and `fovLeft` within the profile file. Always back up your profile before editing. The in-game slider might also correspond more closely to the calculated VFOV, but manual config editing using `fovTop` is more precise.

When reading the results, pay close attention to the `fovTop` value if you plan to edit configuration files, or the VFOV if you are trying to match the in-game slider’s behavior. A higher HFOV gives more peripheral vision but can make targets smaller and introduce a “fish-eye” effect if too high. Lower FOV zooms in but reduces awareness. Find what suits your playstyle using our Arma 3 graphics settings guide.

Key Factors That Affect Arma 3 FOV Results

1. Monitor Aspect Ratio: The width-to-height ratio of your screen is the biggest factor. Ultrawide monitors (21:9, 32:9) will have very different VFOV for the same HFOV compared to 16:9.
2. Desired Horizontal FOV: Your personal preference for how wide you want your view. Higher HFOV increases peripheral vision but can distort the image and make distant objects smaller.
3. Viewing Distance: How far you sit from your monitor can influence your perceived ideal FOV. Closer distances might make higher FOVs more comfortable.
4. Playstyle: Close-quarters combat might benefit from a slightly higher FOV for awareness, while long-range engagements might favor a lower FOV for better target acquisition.
5. Game Performance: A very high FOV renders more of the world, which could slightly impact performance on lower-end systems. See our Arma 3 performance guide for tips.
6. Distortion: Extremely high FOV values, especially on standard aspect ratios, can cause significant “fish-eye” distortion at the edges of the screen.

Understanding these factors will help you choose the best input for the Arma 3 FOV calculator and interpret the results effectively. For more on FOV in general, see our article on FOV in FPS games.

Frequently Asked Questions (FAQ)

What is the best FOV for Arma 3?

There’s no single “best” FOV; it depends on your monitor’s aspect ratio, how far you sit from it, and personal preference. Many 16:9 users prefer an HFOV between 75-90, while ultrawide users might go for 90-110 HFOV. Use the Arma 3 FOV calculator to see the VFOV and fovTop for your desired HFOV.

How do I change FOV in Arma 3 config?

You can edit the `fovTop` and `fovLeft` values in your `.Arma3Profile` file. Back up the file first. These values are calculated by the Arma 3 FOV calculator.

Does FOV affect performance in Arma 3?

Yes, a higher FOV means more objects and terrain are rendered, which can slightly reduce performance, especially on less powerful hardware. However, the impact is usually small compared to other settings.

What is fovTop and fovLeft?

`fovTop` is tan(VFOV/2) and `fovLeft` is tan(HFOV/2). They are parameters Arma 3 uses in its configuration files to define the field of view.

Why does my FOV feel different on an ultrawide monitor?

Because the aspect ratio is different. An ultrawide (e.g., 21:9) is much wider than a standard 16:9 screen. To maintain a similar vertical view, the horizontal FOV needs to be wider, or if you keep the same HFOV, the VFOV will be much smaller. Use the Arma 3 FOV calculator to adjust.

Can I use this calculator for other games?

The formula relating HFOV, VFOV, and aspect ratio is universal. However, how a game implements its FOV settings (e.g., using VFOV, HFOV, or values like fovTop) can vary. This calculator is specifically tailored for how Arma 3 handles FOV with `fovTop`.

What is a good starting HFOV for the calculator?

For a 16:9 monitor, start with 80-90 degrees. For 21:9, try 90-103 degrees. Adjust from there based on your preference after using the Arma 3 FOV calculator.

How does aspect ratio affect FOV?

Aspect ratio (AR) is the ratio of width to height. For a given VFOV, a wider AR means a wider HFOV. For a given HFOV, a wider AR means a narrower VFOV. Learn more about understanding aspect ratio.