Choosing a QR code size for print
Match module size, content length and viewing distance before ordering printed QR codes.
Start with a real layout
Choose the material and expected scanning distance first. A table card, a product label and a window poster need different tests. There is no universal printed width that guarantees every phone will read every code. A long contact card also creates a denser pattern than a short URL at the same physical size.
Preserve the border and sharp edges
Keep the exported four-module quiet zone on all sides. A module is one small square of the pattern. Do not crop the border to fit a design, and keep captions outside it. Use SVG when resizing in design software; use a sufficiently large PNG in documents that do not support SVG.
Approve one sample before a batch
Print a sample on the intended material at the final size. Scan from the intended distance, in normal lighting and with more than one phone. If reading is unreliable, enlarge the code, shorten its content or improve contrast. Keep the tested file and dimensions with your print order so a later resize does not invalidate the test.