When a QR code won’t scan, the cause is usually on your side: a dirty lens, the wrong distance, glare or low light. Clean the camera, step back so the whole code fits with some space around it, and tilt the phone to lose any reflection. If it still won’t read, the problem is probably the code itself: too small, too faded, too little contrast, or printed without the blank border scanners need.
Go through the phone fixes first, since they take seconds. If you made the code and other people can’t scan it, jump to the section on fixing the code.
Fixes on your phone #
1. Clean the camera lens #
Fingerprints and pocket lint soften the image just enough to stop a scanner locking on. Wipe the rear lens with a soft cloth. This fixes more failed scans than anything else.
2. Change the distance #
Too close and the camera can’t focus; too far and the code is too small to read. Start about a foot away and move closer until the code fills around half the frame, keeping all four edges visible.
3. Get rid of glare #
Glossy menus, laminated signs and screens reflect light straight into the camera. Tilt the phone or the code a little until the reflection moves off the code.
4. Add light #
Dim bars, restaurants and parking garages are the usual trouble spots. Use another phone’s flashlight, or a scanner that has one built in.
5. Hold still and square on #
Point the camera straight at the code rather than at a steep angle. QR codes can be read from any direction, but a sharp angle distorts the squares.
6. Check your scanner settings #
- iPhone: on many iOS versions there’s a Scan QR Codes switch in Settings > Camera. If the Camera app ignores codes, try the Code Scanner in Control Center. Our iPhone scanning guide covers both.
- Android: some camera apps have a QR scanning option in their settings that can be off. Google Lens and the Quick Settings scanner tile are alternatives. See how to scan a QR code on Android.
- Scanner apps: a black preview usually means the app doesn’t have camera permission. Check your phone’s app settings.
7. Try a different scanner #
Scanners differ in how well they handle small, dense or damaged codes. If the camera fails, try Lens, the Code Scanner or a dedicated app, and the other way around.
8. For codes on a screen, adjust the screen #
Turn the screen’s brightness up, zoom in so the code is larger, and tilt the phone slightly to reduce the rippled moiré effect. If the code is on your own phone, take a screenshot and read it from the image with Photos, Google Lens or a scanner app that imports pictures.
A dedicated scanner helps with several of these at once. QR Handler has a flashlight button for dim rooms, 1×, 2× and 3× zoom presets plus pinch-to-zoom for small or distant codes like posters across a room, and a Photo button to read codes from screenshots. It also reads the other code types that trip up QR-only scanners, like Data Matrix, Aztec and PDF417.
Fixes on the code itself #
If you made the code and people report it won’t scan, check these.
9. Contrast and colors #
Scanners need a dark code on a light background. Denso Wave, the company that invented the QR code, recommends printing codes black on white, and its FAQ gives the example that a red code on a white background is impossible for red-light scanners to read. Pale colors, gradients, photos behind the code and light-on-dark (inverted) codes all cause failures with some readers. Dark blue, green or purple on white usually works; yellow, light gray or pastel does not.
10. The blank border (quiet zone) #
A QR code needs empty space around it. Denso Wave’s FAQ says a white space four modules wide is needed, where a module is one of the small squares in the code. Designers often crop codes tight against a border or place them against busy backgrounds, and that alone can make them unreadable.
11. Size, density and damage #
- Too small for the scanning distance. A code on a business card is scanned from inches away; one on a poster is scanned from several feet. Size the code for how far away people will stand, and test from that distance before printing.
- Too much data. The more you store, the more and smaller the squares get. A long web address makes a dense code. A short address, or a shorter link you control, makes a simpler code that scans more easily.
- Damage and wear. Scratches, folds, fading and water damage remove parts of the code. QR codes have error correction built in, so a bit of damage is fine, but a lot isn’t. For codes outdoors or on items that get handled, use a higher error correction level; see QR code error correction levels.
- A logo covering too much. Logos in the middle depend on error correction to fill the gap. If you add one, keep it small and use the highest error correction level.
Before printing, test the code with at least two different phones from the distance people will actually use.
When the code scans but nothing happens #
Sometimes the scan works but the result fails:
- The link is dead. The website moved, or a dynamic code’s subscription lapsed. Our article on whether QR codes expire explains why codes stop working.
- The link type is blocked. Some scanners refuse link types that can do harm. QR Handler, for example, only opens web, email, phone and text-message links.
- It’s a Wi-Fi code with a typo. If the password inside the code is wrong, the phone reads it fine and then fails to connect. Scanning with an app that shows the full contents lets you see the password it holds.
Frequently asked questions #
Why is my phone not scanning QR codes anymore? #
A dirty lens, a changed camera setting or a missing permission are the usual causes. Clean the lens, check that QR scanning is switched on in your camera settings, and try a different scanner such as Google Lens or the iPhone Code Scanner.
Can a QR code be too small to scan? #
Yes. Small codes need the phone to be close, and very small or dense codes may not resolve at all on some cameras. Make printed codes bigger for anything scanned from a distance, and test before printing.
Do colored QR codes scan? #
Yes, if the code is dark and the background light with strong contrast. Very light colors, inverted codes and busy backgrounds cause problems.
Why does a QR code scan on one phone but not another? #
Cameras and scanning software differ, especially with small, dense, damaged or low-contrast codes. If you made the code, simplify it: less data, more contrast, a bigger size and a clear border.