The most common reason a QR code does not scan is that it is too small. The second most common reason is bad print quality. Here is a simple guide so you get both right the first time.
The rule of thumb
The minimum size for a QR code to scan reliably is 1 inch by 1 inch (about 2.5 cm by 2.5 cm). That is for a phone scanning from a normal distance of about 12 inches.
If the scanning distance will be further, the code needs to be bigger. A rough formula: divide the scanning distance by 10. That gives you the minimum QR code size. So if someone is scanning from 5 feet away, you need a code that is at least 6 inches wide.
Size guide by print type
| Print Type | Recommended Size | Scan Distance | Notes |
|---|---|---|---|
| Business card | 0.8 to 1 inch | 6 to 12 inches | Put it on the back where it has room |
| Flyer or brochure | 1.5 to 2 inches | 1 to 2 feet | Leave room for a call to action next to it |
| Poster | 2 to 3 inches | 3 to 5 feet | Bigger is always better on posters |
| Storefront window | 3 to 4 inches | 3 to 6 feet | People scan through glass, so go bigger |
| Billboard or banner | 6+ inches | 10+ feet | Test from actual viewing distance before printing |
Print resolution and file format
A QR code that looks fine on screen can turn into a blurry mess when printed. The fix is simple: download the right file format.
SVG is the best choice for print. It is a vector format, which means it scales to any size without losing sharpness. You can blow it up to billboard size and every edge stays crisp. AQRHub lets you download SVG on the free plan.
PNG works too, but only if the resolution is high enough. For print you want at least 300 DPI. A 1 inch QR code at 300 DPI means the image needs to be at least 300 by 300 pixels. For a 3 inch poster code, you need 900 by 900 pixels minimum.
Never use a screenshot of your QR code for print. Screenshots are low resolution and will look fuzzy when printed at any decent size.
The quiet zone and why it matters
The quiet zone is the empty space around all four sides of your QR code. It is not decoration. Phone cameras need that blank area to figure out where the code starts and ends.
The standard rule is 4 modules of quiet zone on every side. A module is one of the small squares that make up the QR code pattern. In practical terms, just leave a border of white space that is roughly the width of 4 of those tiny squares.
Do not let logos, text, or design elements crowd up against the code. If your background is dark, add a white box behind the code that extends past the edges. This is one of the easiest things to get wrong and one of the easiest to fix.
What makes a QR code fail to scan
Too small. This is the number one problem. If the code is under 1 inch and someone is holding their phone at arm's length, it will not scan. When in doubt, go bigger.
Bad contrast. QR codes need a strong difference between the dark modules and the light background. Black on white is ideal. Dark blue on white works too. Avoid light gray on white, or dark colors on dark backgrounds. If you squint and the code blends in, your phone camera will struggle too.
Low print quality. Inkjet printers can bleed, making the modules blur together. Laser printers are better for QR codes. If you are printing a large batch, ask your print shop for a test print first.
Physical damage. A wrinkled sticker, a scratched surface, or a code that has been partially covered by tape or a label. QR codes have some built-in error correction, but they can only recover from so much damage. Keep the code clean and flat.
Too much data. The more information you pack into a QR code, the more modules it needs, and the smaller each module gets. A URL with 200 characters will have much denser modules than a short link. Use a URL shortener or a dynamic QR code to keep the data minimal.
Not sure which plan is right for you? Read our guide on free vs paid QR code generators.
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