Guide · TVs
How big a TV for your sofa? 30° vs 40° explained
Screen size is about one number: how much of your view the picture fills. Two industry standards give that number — 30° and 40° of horizontal view. Measure from your eyes to the screen and the size follows.
30°
SMPTE: the relaxed minimum
The film and TV engineers' society (SMPTE EG-18) puts the minimum at 30°. The picture sits comfortably in view, the room stays around it.
Sit at about 1.6× the diagonal
40°
THX: the cinema seat
THX aims for 40° from the best seat — the screen fills your view like a good cinema row. Better for films and games you want to sink into.
Sit at about 1.2× the diagonal
Distance to size
| Eyes to screen | 30° · SMPTE | 40° · THX |
|---|---|---|
| 1.5 m | 36″ buy 43″ | 49″ buy 50″ |
| 2 m | 48″ buy 50″ | 66″ buy 65″ |
| 2.5 m | 61″ buy 65″ | 82″ buy 85″ |
| 3 m | 73″ buy 75″ | 99″ buy 98″ |
| 3.5 m | 85″ buy 85″ | 115″ bigger than any TV |
| 4 m | 97″ buy 98″ | 132″ bigger than any TV |
Stock sizes: 43″, 50″, 55″, 65″, 75″, 85″, 98″.
Do you need 4K at that distance?
The numbers below use the 1-arcminute rule for 20/20 vision — an engineering rule of thumb, not a guarantee for every pair of eyes.
- With 20/20 vision you stop seeing single pixels once each one covers less than 1/60 of a degree.
- 1080p pixels blend from about 1.6× the diagonal — exactly the 30° seat. Sit there and 4K adds little visible sharpness.
- 4K pixels blend from about 0.8× the diagonal. At the 40° seat (1.2×) 1080p can show its pixels; 4K is past the limit.
- 8K pixels blend from about 0.4× the diagonal — about 65 cm from a 65″ TV.
Full HD1920×1080
2K (QHD)2560×1440
4K UHD3840×2160
8K UHD7680×4320
Try it in your room
Drag the TV along the floor, then switch to From the sofa to see the screen through the viewer's eyes.
82″
Drag the TV along the floor
Standards: SMPTE EG-18 (30° minimum), THX (40° recommended). Pixel limit: 1 arcminute, 20/20 vision. 3D textures and plant: Poly Haven (CC0).
