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QR code guides

The parts people get wrong: sizing, error correction, and assuming a code that works on screen will work on paper.

Why a QR code will not scanNine causes, in the order they actually happen.Static vs dynamic QR codesWhat the difference really costs you, both ways.What size to print a QR codeThe 10:1 rule, and where it stops working.Error correction levels explainedWhat L, M, Q and H actually change.Do QR codes expire?Static codes do not. Dynamic ones can, and often do.

Where to start#

If something is broken right now, read why a QR code will not scan. If you are about to send artwork to a printer, read what size to print a QR code first — it is the cheapest ten minutes you will spend on the job.

If you are comparing products and cannot work out why some generators charge a subscription, static vs dynamic explains what you are actually paying for and when it is worth it.

The three mistakes behind most failures#

Across everything people write to us about, almost every problem traces back to one of three things, and none of them is the generator.

The code was printed too small. A code that scans perfectly on a monitor can be unreadable at 15 mm on a flyer, because a screen renders each module as several crisp pixels and a press does not. The fix is arithmetic rather than judgement: work out the size from the scanning distance and from the grid density, then take whichever number is larger.

The quiet zone was cropped. Designers reclaim the white margin around a code to make a layout fit, not realising it is part of the specification. A scanner uses that blank border to find where the pattern starts. Remove it and detection becomes unreliable in exactly the marginal lighting where you need it most.

Too much was encoded. Every extra character adds modules, and more modules at the same width means smaller squares. A tracking URL with five parameters can double the grid density compared with the clean address it wraps, for no visible benefit on a printed flyer nobody is A/B testing.

What these guides assume#

That you are making codes for something physical — a menu, a label, a sign, a piece of equipment — rather than a screen. Codes on screens rarely fail, because the display does the hard work. Everything difficult about QR codes shows up at the moment ink meets paper, and that is what these guides are about.

They also assume you would rather understand the trade-off than be told a single right answer. Error correction, code size and content length pull against each other, and the correct balance for a business card is wrong for a warehouse label.

Or skip ahead and make one#

The guides are here when you need them, but nothing beats generating a code and testing it. Make a link code, a Wi-Fi QR code generator, a contact card or a text QR code generator, print it at the size you are planning, and scan it on the oldest phone in the office.