Viewing Distance Calculator
Estimate a seat from screen width and a viewing angle. SMPTE 30° and THX 36–40° are published recommendations, plus a 1-arcminute pixel estimate for TVs and monitors.
Viewing distance calculator
At or past the 1-arcminute estimate (4.2 ft (4′3″)), the screen height covers about 1131 arcminutes, compared with 2160 vertical pixels of 4K (about 1080p if each pixel were 1 arcminute). Pixels under 1 arcminute are harder to pick out. This is not a rule that 4K becomes useless.
Distance = (width / 2) / tan(angle / 2), where width = diagonal × aspect / √(aspect² + 1). Field of view = 2 × atan(width / (2 × distance)). The pixel estimate is 1 / (PPI × tan(1′)), when one pixel is about 1 arcminute. It is not an eye test, and it is not a point where 4K becomes useless. The closer-than mark is the larger of a 60° field of view or about 2 arcminutes per pixel. Distances are from your eyes to the screen. A zero or non-numeric size shows a dash.
How to read the numbers
What SMPTE and THX actually say
Both describe an angle, not one correct distance. Distance = (width / 2) / tan(angle / 2). Width comes from the diagonal and the aspect ratio. The SMPTE figure used here is 30° of horizontal view. The THX range used here is 36° to 40°, and 40° is the closer seat. For a 65 inch 16:9 TV that math is about 8.8 feet at 30°, 7.3 feet at 36°, and 6.5 feet at 40°. None of these is a measured best seat.
The 1-arcminute pixel estimate
Pixel distance = 1 / (PPI × tan(1′)). That estimates when one pixel is about 1 arcminute. It is not a medical acuity test, and it is not a rule that 4K becomes useless. On a 65 inch 16:9 screen, 1080p is near that size at about 8.5 feet, and 4K at about 4.2 feet. Closer than those seats, the pixels are wider than 1 arcminute. Farther away, they are smaller. The note under the results compares angular height in arcminutes with the vertical pixel count you picked.
Angle scales with screen size
If the seat is 10 feet from a 16:9 screen, SMPTE's 30° lands near a 74 inch diagonal. A 75 inch set is the nearest common size. If the screen fills a small angle, both 1080p and 4K can sit under the 1-arcminute estimate. That still does not make 4K useless. Distance → screen mode shows the diagonal for each angle at your seat.
Films, games, and desks
Films are a common reason to use the wider THX angles. Some competitive players prefer a smaller angle, around SMPTE or less, so more of the HUD stays in one glance. Racing and flight sims often use a wide view. Match an in-game number with the FOV calculator. At a desk, this page uses 40° to 55°, not SMPTE or THX. A 27 inch 16:9 1440p monitor is near 1 arcminute per pixel at about 80 cm. That is the pixel estimate, not an eye test.
Related tools
Compare pixel size at a distance with the Retina display calculator, work out pixel density with the PPI calculator, set an in-game angle with the FOV calculator, or convert screen dimensions with the aspect ratio calculator.
Frequently asked questions
Is there one correct viewing distance?
No. Distance comes from screen width and a viewing angle: distance = (width / 2) / tan(angle / 2). SMPTE at 30° and THX at 36° to 40° are published recommendations, not a measured best seat. A wider angle means a closer seat for the same screen.
How are SMPTE and THX used here?
SMPTE on this page is a 30° horizontal angle. THX is the 36° to 40° range, with 40° the closer seat. Both are published recommendations. The page turns those angles into a distance from your screen width. It does not measure the room or pick a seat for you.
Does 4K become useless past the pixel distance?
No. That distance is 1 / (PPI × tan(1′)), an estimate of when one pixel is about 1 arcminute. It is not a medical acuity test. Past it, pixels are smaller than 1 arcminute. That does not mean 4K becomes useless.
How is screen width calculated?
Width = diagonal × aspect / √(aspect² + 1). Field of view = 2 × atan(width / (2 × distance)). The 21:9 option uses 64:27, which matches 2560×1080 and 5120×2160. 3440×1440 is slightly wider than 64:27, so that row is only approximate. PPI is horizontal pixels divided by width.
What does monitor mode use for a desk?
It uses 40° to 55°, which is separate from SMPTE and THX. The slider runs from 50 to 100 cm. On a 27 inch 16:9 screen, 1440p pixels are about 1 arcminute near 80 cm. That is the same pixel-size estimate, not an eye test.
What if the size is zero or not a number?
The results show a dash. They do not show Infinity. Inches, centimeters, and feet convert with 2.54 cm per inch and 12 inches per foot. Meters use 0.0254 m per inch. Switching units rounds the field, then the angle math uses that length.
Does this read my screen or my eyesight?
No. You type the diagonal, aspect ratio, resolution, and distance. The browser does not measure the panel, the sofa, or your vision. Saved inputs are written to local storage on this device only after the page has loaded, and only if storage is available.