TV Size Calculator
Enter how far you sit from the screen. We use the SMPTE 30-degree and THX 36–40-degree viewing-angle standards, then check the TV physically fits your wall or stand.
Quick answer: Divide your viewing distance in inches by 1.6 for the SMPTE 30-degree recommendation, and by 1.2 for the THX 36 to 40-degree cinematic recommendation. At 8 feet (96 inches), that gives a 60 to 80-inch TV. Most living rooms land on a 55 to 75-inch screen. Use the calculator above for your exact distance.
The two TV size standards
Two industry standards define how big a TV should look from your seat. Both express the same idea: the screen should fill a set portion of your field of view.
- SMPTE (Society of Motion Picture and Television Engineers): the screen should fill at least 30 degrees of your field of view. Formula: viewing distance ÷ 1.6 = screen diagonal. A 55-inch TV at this standard sits 7 ft 4 in away.
- THX: the screen should fill 36 to 40 degrees for a cinematic feel. Formula: viewing distance ÷ 1.2 = screen diagonal. The same 55-inch TV at the THX standard sits about 5 ft 6 in away.
For mixed daily use (news, sports, streaming), aim between the two standards. For a dedicated movie setup, lean toward the THX end.
TV size by viewing distance
| Viewing distance | SMPTE 30° (comfort) | THX 36–40° (cinema) |
|---|---|---|
| 6 ft | 45 in | 60 in |
| 7 ft | 53 in | 70 in |
| 8 ft | 60 in | 80 in |
| 9 ft | 68 in | 90 in |
| 10 ft | 75 in | 100 in |
| 12 ft | 90 in | 120 in (projector) |
How to measure viewing distance
- Sit where you normally watch and measure from your eyes to the wall or stand where the screen will be.
- Measure in a straight line, not at an angle. Angled measurements inflate the distance.
- Use the main seating position. Secondary seats can be closer or farther without issue.
Common TV size questions
Only if you sit closer than about 6.5 feet. At 8 feet and beyond, 65 inches sits comfortably inside the SMPTE range.
Yes. Higher resolution means smaller pixels, so you can sit closer without seeing pixel structure. The SMPTE/THX angles still apply for immersion, but 4K removes the old penalty for sitting close.
Either works at the right distance. If you use a stand, check our TV stand dimensions guide so the stand fits the TV width with room to spare.
Also see our couch-to-TV distance guide. More calculators: all HomeSizeLab tools.