Why your QR code doesn't scan, and how to make one that reliably does

A QR code that scans perfectly on the screen it was generated on sometimes refuses to scan once it's printed on a flyer, shrunk onto a business card, or displayed on a low-brightness screen across a room. The code itself isn't broken — it's usually a specific, fixable reason a camera can't lock onto the pattern.

What a scanner actually needs to see

A QR code encodes data as a grid of black and white squares, and the three larger squares in the corners are what a scanner's camera looks for first to recognize and orient the pattern before it even starts reading data. Anything that obscures those corner markers, or that reduces the contrast between the black and white regions, makes that initial recognition step fail before the actual data-reading even begins.

The most common reasons a scan fails

• Printed too small — below roughly 2cm/1in per side for a typical amount of data, individual squares become smaller than a phone camera can resolve at normal scanning distance.
• Low contrast — light gray on white, or a color choice that looks fine to a human eye but doesn't register as clearly black-vs-white to a camera sensor.
• A logo or decorative element placed over one of the three corner markers, rather than in the safer central area some QR codes can tolerate a small overlay in.
• Encoding too much data for the physical size it's printed at — a long URL crammed into a small code has finer, denser squares than a short one, which need to be printed larger to stay scannable.

Generating one that holds up

QR Code Generator creates the code from your link or text entirely in your browser, and the practical fix for most scanning problems is upstream of the tool itself: use a shortened link if the destination URL is long, keep the code reasonably large relative to its viewing distance, and test the actual printed or displayed version with a couple of different phones before finalizing artwork.