Why won’t my QR code scan?

Start with the empty border, contrast and physical size. These are common, visible problems that can prevent a camera from detecting an otherwise valid code.

1. Restore the quiet zone

Keep a clear border at least four modules wide around every side of a standard QR code. A module is one small square in the grid. Text, borders, photos and other marks inside this area can make the symbol harder to locate.

2. Use dark modules on a light background

Begin with near-black on white. Avoid inversion, low-contrast colours, transparent backgrounds over photos and reflective finishes. A colour pair that looks distinctive to a person may still be difficult for a camera under poor lighting.

3. Make the code large enough

Scanning distance, payload length, print quality and camera resolution all matter. A dense code contains more, smaller modules within the same physical width. Increase the printed size rather than squeezing complex content into a small space.

4. Check focus, light and surface

• Move the phone closer or farther away until the code is in focus.
• Avoid glare, shadow and strong backlighting.
• Flatten folded material and test curved packaging from several angles.
• Clean the camera lens and make sure the whole code is visible.

5. Remove risky decoration

Logos, rounded modules and covered areas all remove or alter encoded information. Error correction can recover some damage, but it is not a guarantee and does not protect every part of the symbol equally. Test a plain version to separate a styling problem from a payload problem.

6. Confirm what the code actually contains

A successful scan can still lead to a broken page. Use the QR Scanner to view the decoded result before opening it. Check for typing mistakes, expired destination pages and access restrictions.

Before a print run

1. Export a sharp SVG or a sufficiently large PNG.
2. Print a proof at the final size on the final material.
3. Test from the intended distance and angle.
4. Use more than one real phone and realistic lighting.
5. Test the destination as well as the initial scan.

An automated checker can identify useful signals, but no image test can guarantee performance on every camera, material, printer or lighting condition.