QR best practices that actually work

1. 1

   Size

   At least 2 × 2 cm; 1/10 of scan distance.

2. 2

   Contrast

   Dark modules on a light background.

3. 3

   Quiet zone

   Keep 4 modules of margin around the code.

4. 4

   Test

   Scan with iOS Camera, Android Camera, and one third-party app.

The #1 reason QR codes fail is size. As a rule, your QR's edge should be ~1/10 of the expected scan distance — a 30 cm scan needs a 3 cm code.

Contrast matters more than color. Inverted (light on dark) codes technically break the spec; most scanners tolerate them, but don't count on it in production.

Always keep the quiet zone (4 modules of empty margin). Cropping it is the fastest way to make a code unreadable.