Check #1: Contrast
The most common cause. The dots have to be visibly darker than the background. Squint at the QR — if the dots blur into the background, the scanner sees the same thing. Fix: increase contrast, ideally back to dark-on-white.
Check #2: Size
The QR is probably too small for the scanning distance. Try the 10:1 rule — scan distance divided by 10 = minimum QR width. If a customer is reading from 50 cm away, the QR needs to be at least 5 cm wide. Fix: reprint bigger.
Check #3: Quiet zone
A QR with no white margin around it is hard for cameras to detect. Designers love filling that space, but it’s essential. Fix: re-export with a proper margin (4 modules / ~10% of the QR’s width).
Check #4: Logo too big
A logo over 25% of the QR’s width destroys too many modules for error correction to recover. Fix: shrink the logo, increase error correction to level H, or both.
Check #5: Glare or curvature
Printing on glossy, laminated, or curved surfaces creates camera-defeating glare and distortion. Fix: switch to matte paper or a flat surface, or re-position so the QR isn’t directly under a light source.
Check #6: Broken destination
Sometimes the QR scans fine but the link is dead or super slow. Fix: open the destination URL in an incognito browser on mobile data — if it 404s or takes 8 seconds to load, fix the page, not the QR.
Check #7: Damaged or low-res print
A QR resized up from a tiny PNG, or printed at low DPI, ends up with fuzzy dots that camera-decoders trip on. Fix: re-export the QR at the correct resolution and reprint.
Check #8: Old scanner app
A few really old phones or generic third-party "QR scanner" apps fail on styled QRs. Modern iPhones (iOS 11+) and Androids (8+) use the native camera and almost never fail. Fix: ask the user to try with their phone’s native camera before assuming the QR is broken.
- Contrast and size fix 80% of scanning issues
- Always test from the same distance and lighting the QR will be used in
- Keep a backup short URL printed below the code
- If only one phone fails, blame the phone — not the QR
- Re-generate at H error correction whenever there’s a logo
Most "QR not scanning" issues are fixable in under 60 seconds once you know where to look.