TL;DR
- A GS1 Digital Link QR code needs 4 modules of clear margin on every side (a Data Matrix needs 1), dark modules on a light background, and a module size inside the range GS1 sets for where it will be scanned.
- The URL sets the module count: a shorter URL means bigger modules in the same space. For phone scanning, about 2 × 2 cm is a practical floor for a short URL.
- Proof on the real material, scan with several phones and a 2D checkout scanner, and grade the print to ISO/IEC 15415 if the code must ring up at retail.
A GS1 Digital Link QR code scans reliably when its module size suits the scanner and the print process, its quiet zone is empty, and its dark modules contrast clearly with the background. Keep it off folds and tight curves, and test it on the printed pack. Below are the numbers, for QR codes and for Data Matrix where space is tight.
GS1 Digital Link QR code print specs at a glance
| Module (X-dimension) | The width of one square of the code; every other size follows from it |
| Quiet zone | QR code: 4 modules on every side (ISO/IEC 18004). Data Matrix: 1 module (ISO/IEC 16022) |
| Phone scanning | About 2 × 2 cm for a short URL, larger for long URLs or distances |
| Checkout scanning | Module size within the GS1 General Specifications symbol specification tables |
| Colors | Dark modules on a light background; no red, orange or yellow modules |
| Error correction (QR) | Level M by default, Q or H for rough surfaces |
| Print quality | Graded 4 to 0 (A to F) under ISO/IEC 15415 |
What size should a GS1 Digital Link QR code be?
Printed width is the module count multiplied by the module size, plus 8 modules of quiet zone. The URL sets the count; you set the size.
- For phone scanning, about 2 × 2 cm (0.8 × 0.8 in) is a practical floor for a short URL. A common rule of thumb is a code about one tenth of the scanning distance: 5 cm wide for a code read from 50 cm.
- For checkout scanning, GS1 sets a minimum, target and maximum module size for each application in the symbol specification tables of the GS1 General Specifications. Too small and the imager can't resolve the modules; too large and the code may overflow its field of view. Check the current release before you fix the artwork.
How does the URL length change the code?
A QR code grows in versions: each adds 4 modules per side, from 21 × 21 at version 1, and holds a fixed amount of data per error correction level. A longer URL means a higher version, so more, smaller modules in the same space.
| URL | Characters | Version at level M | Modules | Width at a 0.5 mm module | With quiet zone |
|---|---|---|---|---|---|
https://id.example.com/01/09506000134352 | 40 | 3 | 29 × 29 | 14.5 mm | 18.5 mm |
Plus /10/LOT42/21/1234 | 57 | 4 | 33 × 33 | 16.5 mm | 20.5 mm |
Plus ?17=271231 | 67 | 5 | 37 × 37 | 18.5 mm | 22.5 mm |
| About 100, with tracking parameters | 100 | 6 | 41 × 41 | 20.5 mm | 24.5 mm |
The 0.5 mm module only shows the arithmetic; it is not a GS1 value. Versions assume byte-mode encoding.
To keep it compact, use a short domain, encode only the qualifiers you need, and leave tracking parameters out: the resolver can record scans instead. The technology guide covers the URL syntax.
How much quiet zone does the code need?
| Symbol | Minimum quiet zone | Standard | At a 0.5 mm module |
|---|---|---|---|
| QR code | 4 modules on every side | ISO/IEC 18004 | 2 mm |
| Data Matrix | 1 module on every side; more is safer | ISO/IEC 16022 | 0.5 mm |
Measure from the outer edge of the outermost modules. Text, frames and die-cut lines inside it all count as intrusions. For the linear barcode's margin on a dual-code pack, see the dual barcode placement guide.
Which colors and contrast scan reliably?
Checkout scanners use red light, so anything light under red light disappears. That is why a code can work on a phone and fail at the till.
| Combination | Result |
|---|---|
| Black on white | Most reliable |
| Dark blue, green or brown on a light background | Usually reads; test it |
| Red, orange or yellow modules | Fails on checkout scanners |
| Light modules on a dark background (inverted) | Many scanners can't read it |
| Metallic foil or clear film | Unreliable without an opaque white base under the code and quiet zone |
Print the code in one solid dark ink, not a mix of process colors, so registration shifts can't blur it.
Which error correction level should you choose?
| Level | Recovers about | Use when |
|---|---|---|
| L | 7% of the data | Clean print, tight space |
| M | 15% | Most packaging |
| Q | 25% | Rough substrates, abrasion, condensation |
| H | 30% | Heavy handling and damage risk |
Higher levels add modules: the 40-character URL above is version 3 at M but version 5 at H. Error correction is a margin for damage, not room for a logo. Data Matrix (ECC 200) has fixed error correction; you only choose the size. See QR code vs Data Matrix for when each fits.
How do print process and substrate affect legibility?
| Process or substrate | Main risk | What to do |
|---|---|---|
| Flexography | Ink spread makes dark modules grow | Ask the printer for print-gain compensation; avoid very small modules |
| Thermal transfer on the line | Modules that are not whole printer dots | 4 dots at 203 dpi is 0.50 mm; 6 dots at 300 dpi is about 0.51 mm |
| Inkjet or laser marking | Round, uneven dots, lower contrast | Larger modules; verify every setup |
| Gloss film or varnish | Glare | Matte finish over the code area |
| Corrugated board, textile labels | Rough surface, washing, stretch | Larger modules; test after washing |
Where on the pack should the code go?
| Location | Risk | Guidance |
|---|---|---|
| Flat panel | None | Preferred |
| Cans, bottles, tubes | Edges of the code curve away from the camera | Keep the code small relative to the diameter, or use a flat area |
| Folds, seams, glue flaps, crimps | Breaks the grid | Keep the code and quiet zone clear |
| Trim edges, die-cuts | Cutting tolerance eats the quiet zone | Leave extra margin |
For the consumer-facing choice of panel, see where to place a QR code on packaging.
How do you test it?
| Test | Tool | Pass when |
|---|---|---|
| Phones | Native camera apps on two or three iOS and Android phones, at real distance, in low light and at an angle | Opens the right page every time |
| Checkout | A 2D-capable checkout imager, from your retailer or a test lab | Reads the GTIN and parses the GS1 Digital Link URI |
| Print quality | An ISO/IEC 15415 verifier | Meets the minimum grade GS1 sets for your application in its symbol specification tables; 1.5 (C) is the usual retail minimum |
A code can scan on a new phone and still fail grading. If phones scan but the page doesn't open, see why a GS1 Digital Link isn't resolving.
Pre-print checklist for a GS1 Digital Link QR code: nine steps
- Fix the final URL. Decode the code and confirm the domain, the 14-digit GTIN and any qualifiers.
- Choose the symbol and level. QR for consumer packs, Data Matrix where space is tight; level M unless the surface is rough.
- Set the module size. Inside the GS1 range for checkout scanning, and large enough for phones at your scanning distance.
- Export as vector. Place an SVG or PDF and scale it proportionally.
- Clear the quiet zone. 4 modules around a QR code, 1 around a Data Matrix.
- Check the contrast. One solid dark ink on a light background, with a white base on foil or clear film.
- Place it on a flat area. Away from folds, seams, trim edges and tight curves.
- Proof on the real substrate. Use the real print process and material.
- Scan and grade. Test on several phones and a 2D checkout scanner, and verify to ISO/IEC 15415.
Where the Digital Link platform fits
The platform generates GS1 QR codes you can download as SVG, PDF or PNG; use SVG or PDF for print. You can choose a QR code or a QRBARCODE, add a frame and a call to action, and show the GTIN under the code as a fallback for cashiers. Links use the short dlink.is domain by default, and paid plans add custom domains. GTINs are validated on creation, and destinations can change after printing. Create a free account to test a code on your pack.
Frequently asked questions
What is the minimum size for a GS1 Digital Link QR code?
About 2 × 2 cm for phone scanning of a short URL. For checkout scanning, the module size must sit within the GS1 General Specifications range for your application.
How big is the quiet zone around a QR code?
At least 4 modules on every side, per ISO/IEC 18004. A Data Matrix needs at least 1 module.
Can a GS1 Digital Link QR code be printed in color?
Yes, if the modules are dark and the background is light. Avoid red, orange and yellow modules: checkout scanners use red light, and those colors read as background.
Can I put a logo in the middle of the code?
Avoid it on a code that must ring up at the checkout. A logo uses up the error correction margin before the pack leaves the factory.
Is a phone test enough before printing?
No. Phones are forgiving; checkout scanners and verifiers are not. Test both, and grade the print to ISO/IEC 15415.
