QR Code Not Scanning? Here Are the Fixes
When a QR code will not scan, the cause is almost always one of a few simple things: too little contrast, a code that is too small, a busy background, glare, damage or a logo covering too much of the pattern. Work through these fixes in order.
How to use it
Check contrast first
Make sure the code is dark on a light background. Inverted or low-contrast codes are the top failure.
Fix the size and distance
Hold the phone a little further back and make sure the code is large enough for the distance.
Remove barriers
Cut glare, clean the lens, flatten crumpled paper and keep clear space around the code.
Test and regenerate
If it still fails, regenerate the code at higher contrast and size, then reprint and test again.
Tips for best results
Dark on light wins
Never rely on light-on-dark codes. Most cameras read dark modules on a light background far more reliably.
Shrink the logo
Keep any centre logo under about 30% of the code surface so error correction can still rebuild the pattern.
Kill the glare
Tilt the surface or move away from direct light so reflections do not wash out the code.
Leave quiet space
Text, borders or images crowding the code stop scanners locking on, so clear the edges.
Best practices
Test on more than one phone
Different cameras behave differently. Always check new codes on at least two devices before printing.
Check the destination too
Sometimes the code scans fine but the link is broken. Confirm the destination works on mobile.
Avoid very low error correction
Higher error correction lets the code survive scuffs, folds and logos, at the cost of a denser pattern.
Keep links short
Shorter content creates a simpler pattern that scans more easily, especially at small sizes.
Design examples
Washed-out poster
A low-contrast code on a coloured poster fails until reprinted as dark on a light panel.
Over-logoed code
A code with a large logo stops working until the logo is shrunk to under a third of the surface.
Crumpled flyer
A folded code fails until it is flattened or reprinted with a wider quiet zone.
Frequently asked questions
The most likely causes are low contrast, a code that is too small, a busy or glossy background, glare, physical damage, or a logo covering too much of the pattern. Fixing contrast and size solves most cases.
Only if it is too large. QR codes rebuild up to about 30% of missing data through error correction, so keep the logo small and always test before printing.
Cameras and software vary. Older or cheaper phones need higher contrast and a larger code. Testing on several devices catches this before you print thousands.
Usually not reliably. Light dots on a dark background fail on many scanners, so always keep dark modules on a light background.
Error correction stores extra data so the code can still be read when part of the pattern is damaged or covered. Higher levels survive more damage but make the code denser.