How this calculator works
"Optimal" viewing distance comes down to how much of your field of view the screen fills — its viewing angle. A bigger screen at the same distance fills more of your vision; the same screen moved closer does the same thing.Two organizations provide reference viewing angles used in this calculator: the Society of Motion Picture and Television Engineers (SMPTE) uses a 30° viewing angle as a reference for a more comfortable viewing setup, while THX recommends 36° for a more cinematic, immersive experience closer to a movie theater. 40° is included as a more immersive viewing-angle target.
Viewing Distance = Screen Width ÷ (2 × tan(Angle ÷ 2)) Screen width is derived from the diagonal size using the 16:9 aspect ratio standard for TVs, via the Pythagorean theorem.
Worked example
For a seating distance of 8 feet, this calculator recommends roughly a 59" TV under SMPTE's comfortable 30° reference, 72" under THX's cinematic 36° recommendation, and 80" at the 40° immersive viewing-angle target. Going the other direction, a 65" TV calls for a viewing distance of about 8.8 feet under SMPTE, 7.3 feet under THX, and 6.5 feet at the 40° immersive viewing-angle target.
Common TV sizes and recommended viewing distances
| TV Size | SMPTE (30°) Distance | THX (36°) Distance |
|---|---|---|
| 55" | 7.5 ft | 6.1 ft |
| 65" | 8.8 ft | 7.3 ft |
| 75" | 10.2 ft | 8.4 ft |
| 85" | 11.5 ft | 9.5 ft |
Frequently asked questions
How far should I sit from my TV?
It depends on your TV size and preference for comfort versus immersion. SMPTE's 30° reference recommends sitting farther back than THX's 36° cinematic recommendation. For a 65" TV, that's roughly 8.8 feet under SMPTE versus 7.3 feet under THX.
What's the difference between SMPTE and THX viewing-angle recommendations?
SMPTE uses a 30° horizontal viewing angle as a reference for a more comfortable viewing setup. THX recommends 36°, closer to a movie-theater experience, for a more cinematic and immersive picture that fills more of your field of view.
What size TV should I get for an 8-foot viewing distance?
At an 8-foot viewing distance, this calculator gives a recommended screen size of about 59 inches using the SMPTE 30° viewing-angle reference. If you prefer a more cinematic, immersive experience, the THX 36° target gives about 72 inches, while the 40° immersive target gives about 80 inches.
References & Sources
- SMPTE 30° viewing-angle reference: SMPTE Viewing Standards Explained.
- THX 36° viewing-angle recommendation: THX, What Is THX Certified Screen Placement? — official THX guidance
- 40° immersive viewing target: RTINGS, TV Size To Distance Calculator, uses 40° as a recommended distance for a more immersive cinematic experience.