How to make a QR code that always scans
Size, contrast, quiet zone, error correction and content types: the checklist before you print a QR code.
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First: what will the code open?
A QR code is just text turned into an image. The phone decides what to do based on that text's format: if it starts with https:// it opens a website, WIFI: joins a network, a vCard offers to save a contact, and tel: or SMSTO: prepare a call or a message.
Pick the right type in the generator and let it build the format for you; writing it by hand is a common source of codes that “don't do anything”.
Less content, easier scanning
The more text a QR code holds, the more modules (little squares) it needs and the smaller they are at the same print size. A 25-character URL makes a clean code; a 300-character one makes a dense code many cameras won't read from a distance. If the link is very long, use a shorter address on your own site that redirects to the final page.
Size, quiet zone and distance
A few practical rules that prevent most problems:
- Minimum printed size: about 2 × 2 cm for close-up scanning; for posters, roughly one tenth of the reading distance (at 3 metres, 30 cm).
- Always leave white space around it (the “quiet zone”): at least two modules, ideally four.
- Print from SVG or a high-resolution PNG so edges stay sharp.
- Avoid curved, glossy or reflective surfaces.
Colour and contrast
Scanners look for dark modules on a light background. You can use brand colours as long as the code is much darker than the background; inverting them (light on dark) makes many cameras fail. Our generator warns you when the contrast between the two colours is low.
Error correction: when to raise it
The error-correction level says how much of the code can be damaged or covered and still scan: L recovers 7 %, M 15 %, Q 25 % and H 30 %. More correction makes the code denser, so use M for screens and documents and Q or H outdoors, on café tables or if you'll place a logo over it.
Test before you print
Scan it with at least two different phones, from the real distance it will be read at and in the lighting of the place. Follow the link all the way: a perfect QR code leading to a broken page is worse than none.