QR Code Stickers

Size and distance — how they relate

The size a QR code needs depends directly on the distance it will be scanned from. A code on a table, read by a phone at 20-30 cm, works at 2x2 cm, though 3x3 cm is more reliable. On a shop window, scanned from a metre away, the code needs to be at least 6x6 cm. The general rule of thumb: the code's side length should be roughly one tenth of the scanning distance. On top of that, the more data a code holds, the finer its modules — a long URL demands a larger physical size.

• Table (20-30 cm): 2-3 cm
• Wall (50 cm): 5 cm
• Shop window (1 m): 6 cm or more
• Rule: size ≈ distance ÷ 10
• Long URL — finer modules — larger size

Contrast, inversion and the quiet zone

A scanner reads a code through contrast: dark modules on a light field. Inversion — a light code on a dark background — works on some phones and not others, so we avoid it unless the design specifically demands it. The second critical element is the quiet zone: clear space around the code, four module widths wide. If the sticker edge or nearby text crowds the code, the scanner cannot tell where the code ends. That is the single most common reason an otherwise correct code fails to read.

• Dark code on light field — most reliable
• Inversion — does not work on every phone
• Quiet zone: four module widths all round
• Edge or text too close — scanning fails

Material and glare

Two things matter when choosing material for a QR code sticker: durability and glare. A code applied to a table is handled constantly — it needs to be on vinyl with protective lamination, otherwise it wears out within weeks. Glare is the more insidious problem: gloss lamination reflects ceiling lighting and the phone camera cannot see part of the code. So for QR codes we almost always recommend matte lamination — especially on restaurant tables, where light falls from above.