Plain text QR — Settings and quality

Worked example

Text under about 100 bytes stays at 57 x 57 modules or less at level H; for longer text, cut words or split it before lowering correction.

Rough sizes at the default high level: an 18-byte note such as "Room 12, 2nd floor" uses a 29 x 29 grid, a 69-byte message about 49 x 49, and about 119 bytes reaches 57 x 57. At level M the 69-byte message drops to 37 x 37. Past roughly 100 bytes at H the modules get small enough that a printed code needs to be 3 cm or wider to stay comfortable.

Pick the level by environment. For a hotel card handled by guests and kept in a drawer, H with the center mark is reasonable. For a clean screen or a printed page that is never touched, M is acceptable, but test with the center mark on. Remember the default mark covers about 5 percent of the area at 22 percent width; replace it with a smaller image, or keep it, but never above the default on a dense code.

A common mistake is making long text fit by shrinking the quiet border to 0. The border runs from 0 to 48 px; the default is 18 px, and it exists because scanners need a light margin around the pattern. Shorten the sentence instead, or split it into two codes, each with its own label.

Concrete check: at 720 px with the 18 px border, a 49-module code has modules of about 14 px; for a 3.4 cm printed code, modules are roughly 0.6 mm. Export 1000 to 1600 px for posters, and keep dark colours on a light background above the 4.5:1 contrast gate.

Short text, accents and line breaks

Decoded text content

If the text needs more than about 100 bytes, cut words or split it before you reach for lower error correction.