How QR codes work (and why some don't scan)

A QR code is a grid of dark and light squares that encodes text. Three big squares in the corners tell the camera where the code is and how it's rotated. The rest is data plus error correction.

Step by step

1. 1

   Error correction (L/M/Q/H) adds redundancy: at H, up to 30 % of the code can be covered and it still scans. That's what makes logos possible.

2. 2

   Quiet zone is the empty margin around the code. Without it, cameras struggle. Keep the margin setting above 0.

3. 3

   Contrast matters more than color: dark dots on a light background scan best. Inverted codes (light on dark) work on most modern phones but not all scanners.

4. 4

   Size: more content = more squares = needs to be printed bigger. Shorten URLs when you can.

5. 5

   Styling like rounded dots and gradients is fine as long as squares stay distinguishable. Our presets are tested for this.

Tips

• If a code won't scan, first try more light and more distance.
• Static QR codes (like ours) never expire and have no scan limits.

More guides