Printing QR codes that actually scan

Most QR codes that fail in the real world fail for boring, preventable reasons. Get these four right and yours will scan first time.

1. Size

A rough rule: the code should be about one tenth of the distance it will be scanned from. Scanning from arm's length, around 30cm, means a code of about 3cm. A poster read from 3 metres needs about 30cm. Never go below 2cm even for something held in the hand.

2. Leave a quiet zone

The clear margin around the code is part of the code. Cameras use it to find where the pattern starts. Crowding text or a border right up against the edge is one of the most common reasons a code will not read. Leave clear space all the way round, roughly the width of four of the small squares.

3. Contrast

Dark pattern on a light background. Not the reverse — many scanners will refuse an inverted code. Avoid placing it over a photograph or a busy pattern, and be careful with very light colours on white, which look fine on your screen and disappear in print.

4. Download the right file

Use SVG or PDF for anything going to a printer. These are vector files — they stay perfectly sharp at any size, whether it is a business card or a billboard. PNG is fine for screens, websites and social posts, but scaling one up for print gives you soft, blurred edges that scanners struggle with.

Always test the proof

Before approving a print run of a thousand, scan the actual printed proof. Do it in the light where it will really live — a dim bar is not your desk — and try a cheap phone as well as a new one. Thirty seconds here saves a wasted print run.

Use a dynamic code for anything printed

Print is permanent; plans are not. A dynamic code lets you fix a wrong link, or change the destination entirely, long after the ink has dried. It is the difference between a mistake costing nothing and costing a reprint.