QR Code Guides

How QR codes work

A QR code stores data as a pattern of dark and light squares. A phone camera reads that pattern and turns it back into a link, text, Wi-Fi login or contact. Static codes, like the ones on this site, store the data in the code itself, so they do not expire and do not need an account or a redirect service.

Wi-Fi QR codes: the easy way to share your network

Instead of spelling out a long password, print a Wi-Fi QR code and let guests scan it. Use WPA for most home routers, tick the hidden-network box only if your network name is not broadcast, and keep the printed code somewhere only your guests can see it.

Choosing the right print size

For a code scanned from about 30 cm away, print it at least 3 cm wide. For posters scanned from a few metres away, go much larger — roughly 1 cm of code width per 10 cm of scanning distance. Always test-scan the final printed copy.

Error correction: L, M, Q and H

Error correction adds redundancy so a code still scans if part of it is damaged or covered by a logo. L recovers about 7% of damage, M about 15%, Q about 25% and H about 30%. Use H for printed codes and any code with a centre logo, and M or Q for clean on-screen codes.

Design tips that keep codes scannable

Keep strong contrast — dark codes on a light background scan best. Leave a quiet zone of white space around the code. Do not stretch the code, and do not cover more than about a fifth of it with a logo.