LED display size calculator
Pick the display and enter the farthest reading distance — get the digit height that reads at a glance, and the standard sizes we build for it.
From the display to the farthest person who must read it — the entrance, the back row or the far end of the floor.
For 20 m, choose 3″ digits on the forex display board.
| Digit height | Comfortable reading | At your distance |
|---|---|---|
| 1″ (25 mm) | up to about 8 m | Too small |
| 1.5″ (38 mm) | up to about 11 m | Too small |
| 2.3″ (58 mm) | up to about 17 m | Too small |
| 3″ (76 mm) | up to about 23 m | Recommended |
| 4″ (102 mm) | up to about 30 m | Reads easily |
| 6″ (152 mm) | up to about 45 m | Reads easily |
Custom digit heights between and beyond these are built to order.
Digit height vs reading distance.
The rule behind the calculator: about 7.5 metres of comfortable reading per inch of digit height. Maximum legibility is roughly twice this, but a display that has to be squinted at is not doing its job.
| Digit height | mm | Comfortable reading |
|---|---|---|
| 1″ | 25 | about 8 m (25 ft) |
| 2.3″ | 58 | about 17 m (57 ft) |
| 4″ | 102 | about 30 m (98 ft) |
| 6″ | 152 | about 45 m (148 ft) |
| 8″ | 203 | about 60 m (197 ft) |
| 12″ | 305 | about 90 m (295 ft) |
| 18″ | 457 | about 135 m (443 ft) |
| 24″ | 610 | about 180 m (591 ft) |
Choosing an LED digit size.
How do I choose the digit size for an LED display?+
Measure the farthest distance from which someone must read the display — the branch entrance, the back row of a hall, the far end of a shop floor or the boundary of a ground — and allow about 7.5 metres of comfortable reading per inch of digit height. A 4-inch digit reads comfortably to about 30 metres, 6-inch to about 45 and 12-inch to about 90.
What is the difference between comfortable and maximum viewing distance?+
Maximum distance is the farthest point a digit can just be made out; comfortable distance is where it can be read at a glance without effort. Many datasheets quote the maximum, which is roughly twice the comfortable figure. We size for comfortable reading, because a rate, a score or a safety figure is read in passing, not studied.
Should I go one size larger than the calculator says?+
Go larger when the display is read at an angle, against sunlight or glare, by older readers, or when it shows text as well as numbers. Go to an outdoor high-brightness or P10 version rather than simply bigger digits when the board faces direct sun.
Do you make digit sizes that are not in the standard list?+
Yes. The listed sizes are our standard ones; we regularly build custom digit heights, layouts and cabinet sizes in between and beyond them, and confirm the size during the site survey.
Does this apply to P10 LED text displays?+
Roughly. One line of P10 text uses a 16-pixel-high module, about 160 mm (6.3 inches), which reads comfortably to around 45 metres. For full-text P10 displays we size from the number of lines and the reading distance together.