Live NetTV v5.0How the numbers are worked out
The calculator uses two well-established guidelines:
- Viewing angle. The film industry recommends that the screen fills about 30° of your field of view for comfortable everyday viewing (SMPTE), and up to 40° for a cinema-like experience (THX). For a 16:9 screen, that works out to sitting about 1.6 times and 1.2 times the screen diagonal away.
- Visual acuity. A person with 20/20 vision can tell apart details about one arcminute (1/60 of a degree) wide. Once individual pixels are smaller than that from where you sit, extra resolution cannot be seen. That is why 4K only shows its advantage when you sit fairly close or have a large screen.
Quick reference
| Screen | Comfortable distance | 4K visibly sharper within |
|---|---|---|
| 32" | 1.3 m (4.3 ft) | 1.3 m (4.2 ft) |
| 43" | 1.8 m (5.8 ft) | 1.7 m (5.6 ft) |
| 50" | 2.1 m (6.8 ft) | 2.0 m (6.5 ft) |
| 55" | 2.3 m (7.5 ft) | 2.2 m (7.1 ft) |
| 65" | 2.7 m (8.8 ft) | 2.6 m (8.5 ft) |
| 75" | 3.1 m (10.2 ft) | 3.0 m (9.8 ft) |
What this means for streaming
Most live TV channels broadcast in 720p or 1080p, not 4K. From a normal sofa distance, a good 1080p stream on a 50 or 55-inch TV looks just as sharp as 4K would, and it needs a third of the internet speed. If streams look soft, the cause is usually a low-bitrate stream or buffering rather than the TV. Our speed test shows what quality your connection can carry.