What sensor size does the focal length reference?

The calculation uses a 36 mm full-frame sensor width (35 mm film standard). If you use a crop sensor, multiply the result by the crop factor (e.g. 1.5x for APS-C).

What is the difference between horizontal and vertical FOV?

Horizontal FOV spans side-to-side; vertical FOV spans top-to-bottom. Most games quote horizontal FOV, but some (like Source engine games) use vertical. The tool converts between them using your aspect ratio before computing focal length.

Why does a wider FOV produce a shorter focal length?

Focal length and field of view are inversely related. On a 36 mm-wide full-frame sensor, a 120° horizontal FOV corresponds to about 10.4 mm, while a 40° horizontal FOV corresponds to about 49.5 mm.

Is 90° horizontal FOV a standard choice?

Yes. At 16:9 aspect ratio, 90° horizontal FOV corresponds to roughly 18 mm focal length — a wide-angle but not extreme lens. Many FPS games default to 90° or 100°.

Can I use this for vertical monitors or ultrawide displays?

Yes. Enter your actual aspect ratio in the custom field. While a fixed horizontal FOV yields the same focal length across any aspect ratio, games that lock vertical FOV expand horizontal FOV on a 32:9 ultrawide, mapping to a much shorter equivalent focal length.

FOV to Focal Length Game Calculator

Enter a game's horizontal or vertical FOV and get the equivalent camera focal length in millimeters.

FOV Input

FOV Angle (degrees)

FOV Type

Horizontal Vertical

Aspect Ratio

Sensor Width (mm)

Equivalent Focal Length

Enter an FOV angle and click Calculate

FOV Arc Diagram

Common Game FOV Presets (16:9, full-frame)

Game / Context	H-FOV	V-FOV	Focal Length

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Summary

This calculator converts a game's field-of-view (FOV) angle into the equivalent camera focal length in millimeters, referenced against a full-frame 35 mm sensor. Game developers and cinematographers use this to match in-game camera perspective to real-world lens choices. Enter your FOV angle, choose whether it is horizontal or vertical, set your aspect ratio, and the tool instantly returns the equivalent focal length.

How it works

Enter your game's FOV angle (e.g. 90 for horizontal or 74 for vertical).
Select whether the FOV is horizontal or vertical.
Set the display aspect ratio (16:9, 4:3, 21:9, or a custom ratio).
The calculator converts horizontal FOV to the equivalent focal length using the standard formula: f = (sensor_width / 2) / tan(FOV / 2).
The result is shown in millimeters relative to a 36 mm full-frame sensor width.
A visual FOV arc diagram updates to illustrate the angle and perspective.

Use cases

Matching a game screenshot's perspective to a real camera lens for compositing.
Choosing a game FOV that mimics a cinematic 50 mm or 85 mm portrait lens.
Cinematographers researching what real lens approximates a specific gameplay feel.
Game designers setting FOV presets labeled with recognizable focal lengths.
Comparing how FOV changes feel across different aspect ratios.
Film students learning the relationship between angular FOV and focal length.
Content creators picking FOV for recording gameplay that matches a cinematic look.
Calibrating virtual cameras in Unreal Engine or Unity to real lens specs.

Frequently Asked Questions

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