SimSightline / How we calculate
How we calculate
Every number on this site comes from the geometry below and the game data in the table, with sources. If something looks wrong, tell us and we will check it.
Screen size
From the diagonal D and aspect ratio a:b, the picture width and height are:
width = D × a ÷ √(a² + b²) height = D × b ÷ √(a² + b²)
A 27-inch 16:9 screen is 59.8 cm wide and 33.6 cm tall. We use the picture size, not the frame, except where a game asks for the frame (iRacing's Monitor Width).
Flat screens
With eye distance d to the centre of the screen:
horizontal FOV = 2 × atan( width ÷ 2d ) vertical FOV = 2 × atan( height ÷ 2d )
Check: 27-inch 16:9 at 60 cm gives 53.0° horizontal and 31.3° vertical.
Curved screens
A curved screen is an arc of radius R (1000R means 1000 mm) whose centre sits in front of the screen, on your side. The edges wrap toward you. The arc covers an angle θ = width ÷ R seen from that centre. Seen from your eyes at distance d:
horizontal FOV = 2 × atan2( R·sin(θ/2), R·cos(θ/2) − (R − d) )
When you sit exactly at the curve's centre, this equals θ. When R is very large, it equals the flat result. Vertical FOV is measured at the centre of the screen, where curve has no effect.
Triple screens
Each screen, including its bezels, is treated as one side of a shape around your eyes. The side angle that makes every screen face you at the same distance is:
side angle = 2 × atan( (c/2 + b) ÷ (d − s) )
Here c is the straight-line width of the picture (the full width on flat screens), b is the bezel on one edge, and s is how far a curved screen's edges come toward you (zero when flat). Total horizontal FOV is twice the side angle plus one screen's FOV. Our results match the worked examples in the OverTake triple screen guide and the 60° example for 42-inch triples at 80 cm in SimRacingCockpit's iRacing guide.
Game formats and sources
| Game | FOV type | Where to set it | Sources |
|---|---|---|---|
| iRacing Checked | Horizontal | Settings → Display → Monitor | iRacing Support: Setting Up Three Monitors; Trophi.ai: iRacing FOV |
| Assetto Corsa Checked | Vertical | Video settings (in Content Manager or the original launcher) | Driver61: FOV in AC and ACC; Trophi.ai: FOV in AC and ACC |
| Assetto Corsa Competizione Checked | Vertical | Pause menu → View Settings → FOV | Driver61: FOV in AC and ACC; Trophi.ai: FOV in AC and ACC |
| Le Mans Ultimate Checked | Vertical | Settings → Graphics → Visuals → Vertical FOV | RaceControl: LMU FOV and seating; SimRacingCockpit: LMU triple screen setup |
| rFactor 2 Checked | Vertical | In-game graphics / view settings (vertical FOV) | OverTake: Proper triple screen setup |
| Assetto Corsa EVO Community | Vertical | View / camera settings | Dan Suzuki FOV calculator notes |
| Automobilista 2 Community | Horizontal | In-game camera / FOV settings | Reiza forum: FOV, triple screens & immersion |
Still being checked
- F1 25: Uses a slider without degrees. Published conversions disagree, so we are testing before we publish one.
- EA Sports WRC: Slider from 0 to 100. Players report it does not map evenly to degrees.
- RaceRoom: Its FOV handling has changed over the years and current guides disagree on the axis.
- BeamNG.drive: Set in Options → Camera → FOV Tuning; guides disagree on the axis.
- Euro Truck Simulator 2: Players mostly adjust the view by moving the seat; we are confirming the axis.
- Gran Turismo 7 and Forza Motorsport: No free FOV value in cockpit view, so a calculator number cannot be entered.
Rounding
We show one decimal place. Games that accept only whole numbers, such as LMU, get a rounded value. A difference of half a degree is not visible in practice.
Changelog
- October 2026: Launched with iRacing, Assetto Corsa, ACC, LMU, rFactor 2, AMS2 and AC EVO. Curved and triple geometry checked against published examples.
Found a problem? Email contact@simsightline.com with your game and setup.