Scan check: will my QR code scan?
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What “Scans well”, “May be hard to scan” and “Won't scan” mean under the editor preview, how the scan check works, and how to fix a code that fails it.
Under the preview in the editor there's a small colored chip: Scans well, May be hard to scan or Won't scan. That's the scan check. Every time you change the content or the style, QR Crab tries to read your code the way a phone would and tells you how it went, so you catch a code that won't scan before you print it.
- The check reads the preview three ways: at full size, shrunk (like from a distance), and shrunk and slightly blurred.
- Scans well = read correctly all three times. May be hard to scan = only some of the time. Won't scan = never, or as the wrong content.
- Downloading a code that won't scan asks you to confirm first.
How the scan check works
A moment after you stop typing or adjusting, the editor takes the preview (including the frame, logo and margin) and decodes it three times: at full size, at 45% of the size, and at 45% with a slight blur. That's roughly what a phone camera sees from further away or slightly out of focus. A transparent background is checked on white, like paper. It also checks that what it reads matches your content exactly.
Hover over the chip (or focus it with the keyboard) for a short explanation of the result. A little further down, the editor may also list style warnings, such as low contrast or a small margin. Those are rules of thumb. The scan check is the actual test.
What each result means
| Chip | What happened | What to do |
|---|---|---|
| Scans well | Read correctly at full size, small and slightly blurred. | Download it, then test a printed copy with your phone. |
| May be hard to scan — try more contrast, a smaller logo or error correction H | Read at full size, but not every time when small or blurred. | Phones in poor light or far away may struggle. Improve the style, or at least test carefully before printing. |
| May be hard to scan — light codes on a dark background don't work in every camera app | Only readable as an inverted (light-on-dark) code. | Fine for most phone cameras, but some scanner apps fail. Switch to dark dots on a light background if you can. |
| Won't scan — use darker dots on a light background, a smaller logo or error correction H | Couldn't be read at all. | Fix the style before you print it. |
| Won't scan — it reads as different content | Read, but as something other than your content. | Simplify the style or use error correction H. |
Downloading a code that won't scan
When the latest check says Won't scan and you click Download, the editor asks: “Our scan check couldn't read this code, so phones probably can't either. Download it anyway?” Choose Cancel to go back and fix the style. Codes that May be hard to scan download without a question, so it's worth checking the chip yourself.
How to get to “Scans well”
- Read the message. The text after “May be hard to scan” or “Won't scan” already names the likely fix.
- Fix the contrast first. Under Dots and Corner eyes, use a dark color; under Background & shape, a light one. Turn off Gradient if one of its colors is pale.
- Shrink the logo. Under Logo, lower the Size, and make sure Clear the dots behind the logo is ticked.
- Raise error correction. Under Advanced, set Error correction to High (30%).
- Simplify the shapes. Try the Classic or Rounded preset, or plainer dot and corner styles. Presets keep your logo and frame.
- Wait for the chip to update. The check reruns a moment after every change. Stop when it says Scans well.
Still stuck? How to design a QR code: colors, logo and frames explains every style option, and QR code not scanning? How to fix it covers problems that only show up once the code is printed.
What the scan check can't tell you
- Print size and distance. A code that scans well on screen can still be too small for a poster across the room. See How to download and print your QR code.
- Paper and surface. Glare from glossy paper, curved bottles, creases and smudged ink all happen after the download.
- Every phone and app. The check uses one decoder. Phone cameras are usually better at reading codes, but older scanner apps can be worse.
- Whether the destination works. It checks that the code reads correctly, not that the website or page behind it loads.
Common questions
Does “Scans well” guarantee every phone will scan it?
No. It's a strong sign the design is fine, but the check reads your on-screen preview. It can't see how big you'll print it, the paper, the light, or how far away people will stand. Always scan a printed copy with your own phone before printing many.
Can I still download a code that won't scan?
Yes. You'll be asked “Our scan check couldn't read this code, so phones probably can't either. Download it anyway?” and can choose OK. We don't recommend printing it.
Is my code sent anywhere for the check?
No. The check runs in your browser on the preview image.
The chip disappeared. Is something wrong?
No. It's hidden while the preview is still drawing, or when the preview can't be read for the check. It comes back after the next change.
What does “it reads as different content” mean?
The checker managed to read the code, but got something other than what you entered. The style is confusing the decoder. Simplify the shapes or raise error correction to H until it reads correctly.