How to choose LED video wall pixel pitch for close viewing

What decides the pitch

Three inputs decide it, in this order.

1. Nearest viewer. A pixel becomes invisible when the angle it makes at your eye drops below what you can resolve. Design to the closest spot a visitor will stop at, never to the average.
2. Content. Full-motion video tolerates visible pixel structure at short range; viewers read the structure as texture. Small text does not: letterforms break up when each letter is only a few pixels tall.
3. Wall size. Size fixes the pixel count at every pitch, and the quote tracks every pixel. Going from 1.0 mm to 0.9 mm on a 7 m wall adds 778 px of width (7,000 px at 1.0 mm, 7,778 px at 0.9 mm).

The two viewing-distance rules

Comfort rule: 1 m of distance per mm of pitch. The trade quotes this as a rule of thumb, and it carries margin for average eyesight, visitors in motion and the seams between cabinets. Use it when the wall plays video and imagery and nobody has to read small type.

Acuity rule: pitch ≤ distance ÷ 3.44. 20/20 vision resolves about 1 arcminute, which is 0.000291 radians. One LED becomes invisible when pitch ÷ distance falls below that, so the pixel-free distance is pitch × 3440. Turned around for design, with distance in metres and pitch in millimetres:

Use the acuity number when the wall carries text or data people must read. Use the comfort number for video walls, where close-range pixel structure reads as texture.

Sizing the type and the canvas

Letter height and distance follow the planning figure used for any sign: 30 ft of viewing distance per inch of capital letter height (FHWA), which is 0.36 m per millimetre of capitals. For text that must be read comfortably and quickly, use the safer figure, 20 ft per inch, or 0.24 m per millimetre. Set line spacing at 1.7 × capital height. The guide to screen size and viewing distance works these numbers for ordinary screens.

So capitals in mm = distance in m ÷ 0.24. At 2 m that is 8.3 mm, so 9 mm capitals. At 3 m it is 12.5 mm, so 13 mm capitals with 22 mm of line spacing.

Then come the pixels: capitals in pixels = capital height ÷ pitch. A 13 mm capital is 22 px tall on a 0.6 mm wall and 9 px tall on a 1.5 mm wall, and the letterforms show it. That pixel count is why text, never video, is what forces a fine pitch.

The canvas matters too. One player canvas tops out at 3840 × 2160, and every class in the table below carries more width than that on a 7 m wall, so the picture arrives tiled by a processor or split across feeds. The 3840 × 2160 canvas cap and the 4K canvas fix covers the cap, and why a six-screen wall drops to HD per screen shows what tiling does to each tile.

Pitch options for a 7 m × 1.4 m wall

The pixel counts assume the full 7 m × 1.4 m is active area. Real walls build up from whole cabinets, so the final drawing sets exact counts; use the table to compare classes.

Past 6 m the question changes character: a 2.5 mm wall on these dimensions is 2,800 × 560 px, and pitch stops being the expensive line item.

Worked example: a 7 m × 1.4 m wall with close pass-by traffic

Inputs. Wall 7 m wide × 1.4 m tall in an exhibition hall, visitors passing as close as the metre mark (the case this article sizes). Reading line: 3 m, taken as the distance where most visitors stop to read; rerun the steps with your own number if your hall differs. Acuity basis: 1 arcminute = 0.000291 rad for 20/20 vision. Letter-height basis: the safer planning figure, 0.24 m per mm of capitals.

Rules in words. A pitch is pixel-free from a distance when distance = 3440 × pitch. Text is sized when capitals in mm = distance in m ÷ 0.24.

Arithmetic.

1. Strict requirement at the nearest viewer: 1,000 mm ÷ 3440 = 0.29 mm pitch. No purchasable class sits there. A 0.4 mm class reaches 0.4 × 3440 = 1,376 mm, so it turns pixel-free just past that and still shows structure at the metre mark.
2. Candidate walls: at the 0.9 class, 7,000 ÷ 0.9 = 7,778 px wide and 1,400 ÷ 0.9 = 1,556 px tall, which is 7,778 × 1,556 = 12.1 Mpx. At 0.6 mm, 11,667 × 2,333 px. At 0.4 mm, 17,500 × 3,500 px, 61.3 Mpx. One 3840 × 2160 canvas holds 8.3 Mpx, so all three need tiling.
3. Text at the 3 m line: capitals 3 ÷ 0.24 = 12.5 mm, so 13 mm capitals; line spacing 1.7 × 13 = 22 mm. On the 0.9 class those capitals stand 13 ÷ 0.9 = 14 px tall; on 0.6 mm, 22 px; on 1.5 mm, 9 px.
4. Pixel-free lines: 0.9 × 3440 = 3,096 mm, clean from 3.1 m; 0.6 × 3440 = 2,064 mm, clean from 2.1 m; 1.5 × 3440 = 5,160 mm, clean from 5.2 m.

Result. The 0.9 class carries 3 m text with 14 px capitals and turns pixel-free just past the 3 m line, for 12.1 Mpx of wall. The 0.4 mm class spends 61.3 Mpx to move that line from 3.1 m to 1.4 m and still shows structure at the closest pass-by distance. The arithmetic settles the internal buy-in question directly: a pixel-free picture at the metre mark is out of reach at any pitch, so 0.4 mm is not required. The requirement that decides money is the reading line.

Decision. Text or data read from 3 m: the 0.9 class. Text read from 2 m: the 0.6 mm class, pitch ≤ 2 ÷ 3.44 = 0.58 mm. Video and imagery with no small type: 1.2 to 1.5 mm under the comfort rule. Reading at arm's length: no LED pitch serves it, and that job moves to an LCD panel.

When an LCD panel is the closer-reading answer

Inside 2 m, an LCD beats any LED pitch. The pixel pitch of a 1920 × 1080 panel is its diagonal divided by 2,203 pixels (1920² + 1080² works out to 2,202.9 px across the diagonal). A 15.6-inch panel is 396.2 mm across, so 396.2 ÷ 2203 = 0.18 mm, pixel-free from 0.18 × 3440 = 0.62 m. A 21.5-inch panel is 546.1 mm across, so 0.25 mm, pixel-free from 0.85 m. At 1 m both show a picture with no visible pixel structure.

So split the job. The LED wall carries atmosphere, sponsor loops and wayfinding seen from across the hall; LCD panels at the information points carry timetables, room lists and touch lookups. Our panel-mount series covers this size class; see the panel-mount display range. For the foyer version of the same pattern, see our lobby displays.

What to ask for before you sign

• A demo of the exact pitch with your own files loaded, judged from the two distances in the example: the closest pass-by spot for the impression, 3 m for the text. Sub-millimetre demo walls take time to arrange, so book early.
• Native resolution and the drive chain. Ask how many pixels the wall carries and what feeds it. A 0.9 mm wall on 7 m needs 7,778 px of width, past one 4K canvas, so the answer will be a processor or a tiled canvas; how an Android signage player drives an LED wall covers the player side.
• Module size and seam positions, so the drawing places seams away from faces and type.
• Pixel packaging (SMD or COB), with documented failure figures and service arrangements for a wall visitors can touch.
• Brightness in nits, matched to the hall's lighting and calibrated cabinet to cabinet, so the wall reads as one picture.
• Cabinet depth, weight and service access, for the mounting and power design behind the wall.

Recommendation: set the pitch from the closest distance at which the content must look pixel-free, using pitch in mm ≤ distance in m ÷ 3.44. For the 7 m × 1.4 m exhibition wall with visitors at the metre mark and text read from 3 m, buy the 0.9 class. Step to 0.6 mm only when visitors read from 2 m, take 1.2 to 1.5 mm when the wall plays video and imagery watched from 4 m and beyond, and put every close-reading job on a 1920 × 1080 LCD panel, which is already pixel-free from 0.85 m in a 21.5-inch size.

Questions