TVHow TVDistance calculates screen size & distance
Every number on this site comes from simple, transparent geometry — no guesswork. Here's exactly how it works and where the limits are.
The geometry
All screens here are 16:9. For any diagonal D, the picture is D × 0.8716 wide and D × 0.4903 high. Viewing distance is derived from the target viewing angle — how much of your field of view the screen fills.
| Immersive (THX) | ~40° field of view ≈ distance = diagonal × 1.2 |
| Mixed use (SMPTE) | ~30° field of view ≈ distance = diagonal × 1.6 |
| Closest for 4K | ≈ distance = diagonal × 1.0 (pixels invisible) |
| Viewing angle | 2 × arctan((width ÷ 2) ÷ distance) |
Where the numbers come from
The THX and SMPTE viewing-angle recommendations are long-standing industry standards for cinema and home theater. The 16:9 width/height ratios are exact for modern widescreen TVs. Projector throw distances use the standard throw-ratio definition (distance ÷ screen width).
Limits & honest caveats
Eyesight, subtitles, motion sensitivity, mount height, source quality and personal preference all shift the "best" result. Projector placement additionally depends on your exact model's throw ratio. Treat every figure as a well-founded starting point, then trust your own eyes.
Last reviewed 2026-08-12.