Nothing is more frustrating than a QR code that does not scan. Worse, if it is already printed on thousands of flyers or product labels, it is an expensive mistake. Here are the seven most common reasons QR codes fail to scan and exactly what to do about each one.
1. The QR Code is Too Small
The most common reason. For a QR code to be reliably scanned from a normal viewing distance (20–30cm), it needs to be at least 2.5cm × 2.5cm. For signage viewed from further away, scale up proportionally. A useful rule: your QR code should be 1/10 the size of the maximum scanning distance. Scanning from 1 metre? Your QR code needs to be at least 10cm × 10cm.
2. Insufficient Contrast
QR code scanners work by detecting the contrast between dark modules and the light background. If your QR code is printed in light grey on white, or dark blue on black, the scanner struggles to distinguish the pattern. Always maintain strong contrast. Black on white is the gold standard. Dark colours on light backgrounds work well — light on dark is riskier.
3. No Quiet Zone
The quiet zone is the blank white border around the QR code. It tells the scanner where the QR code begins and ends. If your design crops into this border — common when designers tight-crop a QR code — the scanner cannot locate the code. Ensure a quiet zone of at least 4 modules (the white border) on all four sides.
4. Print Quality Issues
A QR code printed on a low-resolution printer, an inkjet that bleeds, or on highly textured paper may not scan reliably. Use a minimum of 300 DPI for print. If your QR code will be printed on packaging or textured materials, test a physical sample before committing to a print run.
5. The Logo is Too Large
Logos placed in the centre of a QR code are supported — QR codes have built-in error correction for this purpose. However, the logo must not cover more than 30% of the QR code area. Above this threshold, the error correction cannot compensate and the code fails to scan. QR Stats enforces a 30% maximum automatically.
6. The Destination URL is Broken
The QR code may scan perfectly but the destination link returns a 404 error or the page no longer exists. Always verify the destination is live after creating your QR code, and check it periodically for dynamic QR codes. QR Stats health monitoring can automatically alert you to broken links.
7. The QR Code is on a Reflective or Curved Surface
Shiny packaging, metallic labels, and curved surfaces (bottles, cans) create reflection and distortion that confuse QR scanners. Use matte finishes for QR code labels on shiny packaging. For curved surfaces, generate a QR code with higher error correction (level Q or H) which is more tolerant of distortion.