How big should the QR code on your box be?
At least 20 mm, with a clear margin, dark on light, somewhere the customer will still find it in two years. Here is the reasoning, and how to check the artwork before it goes to the printer.
- Last reviewed
- Reading time
- 6 min read
How big should the code be?
Print the code at 20 mm square or larger. That is the minimum we recommend for ItemDocs codes, and the size the ItemDocs scan test decodes the artwork at.
Size matters because what a phone actually has to resolve is the module, the smallest square in the code. The more data a code holds, the more modules it has, and the smaller each one gets at a given print size. An ItemDocs code encodes a short address (the product page plus a marker that counts the open as a scan) with medium error correction, which gives a grid of 29 × 29 modules. At 20 mm that is roughly 0.7 mm per module, comfortably readable by phone cameras at arm’s length.
Go larger when:
- the code will be read from a distance, such as on a machine, a shelf-edge display or the side of a large carton (a common rule of thumb is a code width of about a tenth of the scanning distance);
- it is printed on a rough, textured or curved surface;
- the print process is coarse, such as flexographic printing on corrugated board.
A code that encodes a long address, such as a full PDF link with tracking parameters, has more modules and needs to be printed larger for the same reliability. That is one more reason to encode a short, permanent address.
- Quiet zone
- 4 modules, kept clear of print
- Typed fallback
- If the code is scratched
Leave a quiet zone
Scanners find a QR code by its edges. The QR specification (ISO/IEC 18004) calls for a quiet zone, a blank margin four modules wide, on all four sides. At 20 mm that is about 2.8 mm. Designers often fill it with a border, a frame, a logo or the edge of the panel; each makes the code harder to read.
ItemDocs downloads (SVG, PNG and the print-ready PDF) include the quiet zone. Don’t crop it when placing the artwork.
Contrast, colour and finish
- Dark on light. Black or a very dark colour on white or a pale background. Some phones don’t read reversed (light-on-dark) codes.
- Strong contrast. Avoid mid-tones, metallic or fluorescent inks, and printing over a photo, a gradient or a pattern.
- Matt finish. Gloss lamination and shrink-wrap reflect light straight back into the camera. If the box is glossy, test under a ceiling light.
- Flat and whole. Keep the code off folds, seams, corners and tight curves. On a cylinder, keep the code small relative to the curve or turn it so the curve runs along one axis.
- No styling. Rounded modules, logos in the centre and colour gradients all eat into error correction. ItemDocs codes are plain on purpose.
Where to put it, by product type
Put one code where the customer looks first, and one where it survives. The box is thrown away within days; the product stays for years.
| Product type | First look | Long term |
|---|---|---|
| Kitchen and home appliances | Front or top of the box; the first insert | A label near the rating plate, under the base or inside the lid |
| Consumer electronics | Box and inner tray; the quick-start card | On the device if there is room, otherwise the charging case or power adapter |
| Tools and machinery | Carton and safety leaflet | A durable label next to the rating plate |
| Furniture | Every carton, beside the box number | Inside a panel, the back of a drawer or the underside of a seat |
| Lighting | Box and installation sheet | Inside the base or on the canopy |
| Small items | Pack and insert | The insert or the warranty card |
Wherever the code goes, print the ID and short address directly underneath, for example itemdocs.com/i/K7M4X9. If the code is scratched or the customer is on the phone with support, the ID still leads to the page. ItemDocs IDs avoid O, 0, I, 1 and L so they can be read aloud without mistakes.
The words next to the code
A bare code gets fewer scans than one that says what is behind it. Keep it short and concrete:
- “Scan for the manual, setup video, warranty and support”
- “Scan to register your warranty”
- “Assembly video and spare parts: scan here”
The ItemDocs print-ready PDF is a 60 × 80 mm label with the code, the ID, the short address and a caption you choose, which your packaging team can scale or place as it is.
Test before you print
- Test the final print file, not the design draft, at the size it will be printed.
- Scan it with at least two phones, one of them a few years old, using the built-in camera app.
- Test in poor light and at an angle, and through any film or lamination.
- Check that the right product page opens, with the right model name.
- Check that the ID under the code matches the product, and that the short address works when typed.
- Print a proof on the real material before the full run.
In ItemDocs, the built-in scan test decodes the PNG and SVG artwork, including a rendering at 20 mm, then checks that the page responds, that it shows the right product, and that its documents and videos load. A product’s code can be approved for print only after the test passes. See how it works.
Sources
Checked
Links open the original documents.
- [1]ISO/IEC 18004:2024, QR code bar code symbology specificationISO — Defines the symbol structure, error correction levels and the quiet zone.
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