How small can a QR code be?

Start with distance and density

A common planning rule is to make a code about one tenth of the distance from which it will be scanned. Treat that as a starting estimate, not a standard or guarantee.

Longer content creates more modules in the same square. Those smaller modules are harder to reproduce and read, so a dense code often needs a larger printed width.

Leave room for the margin

The required quiet zone is at least four modules of clear space on every side. Designers often measure only the visible symbol and forget this extra area.

Fine paper, low-quality print, glare, folds and dim lighting all argue for a larger code. A phone that scans a bright monitor may struggle with a small code on textured stock.

Test a real copy

Print at final size on the intended material. Check it at the real viewing distance, under ordinary light, with the cameras your audience is likely to use. If it fails, increase the size, shorten the content, or improve contrast.