In short
- Use the GS1 UK barcode generator after allocating the correct GTIN to your product. For an EAN-13 at 100% magnification, the nominal symbol width is 37.29 mm and the minimum bar height is 22.85 mm; reserve additional space for the human-readable digits and keep the required clear margins.
- Generating an image does not license a number, verify the product record or approve the finished print. Treat those as separate checks.
- Dark bars on a light background are the safe starting point. Red bars, a transparent background over changing contents and cropped clear margins can undermine readability.
- Approve a printed sample on the actual packaging. A successful scan with one device is useful, but does not replace formal barcode verification when required.
- AirPost is a peer-to-peer fulfilment network: online shops have their orders packed and dropped at a parcel point by verified people near their customers, who earn a fee per parcel from home. No warehouse, no minimum order volume.
Your designer asks for the barcode file before finalising a product sleeve. It is tempting to paste the digits into the first generator you find and approve the preview. The file can look convincing while encoding the wrong product or leaving too little room on the finished pack. For a UK shop supplying retail products, the useful deliverable is a confirmed number, a suitable image and a print specification that survives the move from screen to packaging.
What must be ready before I generate the image?
Confirm the allocated GTIN and the product it describes. Record the selling unit, the product reference and the approved packaging version together. GS1 UK describes its image generation service as working from your allocated list of GTINs. That link matters: the artwork should start from the confirmed product record rather than a number retyped from an old email. If a supplier owns the product identity, obtain its confirmed code instead of allocating a different identity simply because you are preparing a new label design.
Tell the designer where the product will be scanned. An EAN-13 product symbol is a different deliverable from a logistics label or a courier label for one customer order. Ask a trading partner for its actual barcode specification when supplying a distribution centre or retailer. Do not assume that a code which works on your desk meets every receiving requirement. Freeze the intended application before choosing the image, so a later packaging review has a clear standard to check against.
Which generator should I use for an allocated GS1 UK number?
Start with GS1 UK’s Create barcodes for your products service. Its published guidance also points to approved partners for generation services. You can ask your packaging supplier whether it can produce the required GS1 symbol as part of its artwork process. Whichever route you use, provide the same confirmed GTIN and scan environment. Agree who is responsible for the final print proof. A generator choice should lead to a reproducible file and specification, rather than a collection of screenshots with unclear settings.
When reviewing an alternative tool, check which symbol it is creating and what it includes around the bars. A tool offering Code 128, EAN-13 and QR options is not telling you that all three are interchangeable. Read the output digits back and compare them with your approved product record. Keep the original export and the placed artwork version. If the designer later resizes the placed image, you need to know that the print dimensions have changed even though the original generator file remains correct.
| Release field | What to record | What it prevents |
|---|---|---|
| Encoded identity | Confirmed GTIN and exact selling unit | An attractive file for the wrong product |
| Application | Retail EAN-13 or the separately agreed specification | Using a shipping or internal code as a product symbol |
| Print geometry | Final width, bar height and clear margins | Uncontrolled scaling after export |
| Material and colour | Actual substrate, background and ink combination | A proof that behaves differently on the real pack |
| Approval evidence | Artwork revision, printed sample and checks performed | Mixing an obsolete proof with a new production run |
How much space should an EAN-13 occupy on the pack?
GS1’s published EAN-13 specification gives a nominal width of 37.29 mm, a narrowest bar or space of 0.330 mm at nominal size, and a minimum bar height of 22.85 mm. The supported magnification range is 80% to 200%. Keep the measurement definitions clear: bar height is not the complete height of an artwork box containing readable digits. Ask the printer for the whole required area rather than squeezing the symbol into a rectangle based on one measurement from a comparison chart.
The same specification lists nominal clear margins of 3.63 mm on the left and 2.31 mm on the right. Those blank areas are part of the reading space. Do not let a decorative border, illustration or cutting line intrude into them. If the label template automatically trims unused white space, review the exported result. A barcode image with its margins present can lose them when placed into a tight design frame. The file needs enough room in the final layout, not merely in its original preview.
Keep the shape proportional when changing magnification and ask your printer to confirm the dimensions for its process. Do not shorten only the bars to make room for promotional text. If the available panel is too small, reconsider the panel or obtain advice about an appropriate symbol and allocation. Shrinking a GTIN-13 into an EAN-8-looking image does not turn it into an assigned GTIN-8. The product identity and the physical space problem need their own valid decisions.
Can I print the bars in my brand colour?
GS1 UK’s colour guidance recommends black bars on white. It explains that scanners commonly use red light, making red and reddish bar colours unsuitable. It also warns against light bars on a dark background. Use this as a design constraint before selecting the packaging palette. A colour that looks dark to your eye can behave differently under the scanner’s illumination. If you want another ink combination, have the actual result checked rather than treating visual contrast on a monitor as sufficient evidence.
On a transparent or partly transparent substrate, provide a dependable background. GS1 UK specifically cautions against relying on the colour of the pack contents. A sleeve that scans over one dark product may behave differently over another. For your approval sheet, record which material and backing were tested. Ask whether the print needs a backing layer and how the printer will reproduce it. Changes to the contents, finish or ink should trigger a review of the affected proof, even when the encoded digits have not changed.
What should I check on the first printed sample?
Use a sample produced with the intended material and print settings. Place it on the finished pack, with the usual folds and closures present. Check whether it sits on a stable surface and whether the clear margins remain unobstructed. Compare the measured dimensions with the agreed specification. Read the printed digits against your product record before scanning. That sequence catches a correctly printed barcode for the wrong product, which a successful scanner beep alone cannot reveal.
- Confirm the sample’s product reference and artwork revision.
- Check the encoded number against the approved GTIN record.
- Measure the final printed symbol and inspect its clear margins.
- Test the actual pack with the intended reading equipment and record the returned data.
- Obtain formal verification where your receiving partner requires it, then approve that production specification.
A scan checks an interaction between one symbol, one device and the conditions of that attempt. Verification evaluates symbol quality more systematically. GS1 UK describes verifiers as tools for checking quality, including contrast. Ask your receiving partner what evidence it expects before a large print run. Keep a failed sample and its settings when making a correction, so the printer can compare the change. Do not report only that it did not beep; report the material, file revision and visible problem as well.
How does the product barcode fit into fulfilment?
When you outsource packing and dispatch, the person holding your stock needs a clear relationship between the labelled product and the order line. AirPost’s copy describes stock and orders being coordinated through the shop’s conversation with its sender. Agree what to do when the printed code or product description differs from the instruction. Do not infer that AirPost provides a barcode verifier or automatic scan enforcement. Your artwork approval prepares the stock for the agreed workflow.
Keep the retail product symbol separate from the carrier label applied to the outbound parcel. The product may retain the same GTIN across repeated orders, while each booked shipment has its own label. Make sure a packing instruction says which code identifies the item and which label belongs to the customer parcel. For the equipment decision, the separate guide to a small business label printer covers shipping print needs; it does not approve an EAN-13 artwork specification.
A one-parcel fulfilment trial can expose an unclear product label before wider stock distribution. Using the AirPost constants checked on 14 October 2026, the platform component is €0.85 and the recommended small-parcel sender component is €2.25: €3.10 before carriage and materials. Two separate small-parcel trials have €6.20 of those components. These are euro reference values from the constants, not a sterling carrier quote, a barcode subscription price or a promised saving.
After approval, give your supplier one current artwork version and make obsolete versions easy to identify. Keep a retained sample with the release sheet. At the next stock receipt, compare the physical print with that approved version rather than merely trusting the delivery note. The inventory receipt workflow explains the surrounding stock checks. Your barcode process is complete when the correct identity is readable on the actual goods and everyone handling them can find the right reference.
Frequently asked questions
Does the GS1 UK barcode generator give me a new GTIN?
Image generation uses an allocated product identity. Licensing and assigning the number are separate steps; creating a picture does not register arbitrary digits to your business.
What size should an EAN-13 barcode be?
At nominal size, its width is 37.29 mm and its minimum bar height is 22.85 mm. Keep room for readable digits and the clear margins; confirm the final print dimensions with the printer.
Can I make an EAN-13 smaller to fit my label?
The published magnification range is 80% to 200%. Preserve the geometry and have the printer assess the actual process. Cropping margins or shortening bars is not a substitute for a suitable layout.
Can barcode bars be red?
GS1 UK warns against red and reddish bar colours because scanners commonly use red light. Black bars on a dependable white background are the recommended starting point.
Is scanning the sample enough to approve the print run?
It is a useful functional check, but one successful read does not replace formal verification where the receiving partner requires it. Keep the returned data and the specification of the printed sample.
Sources
Register your shop and agree a packing trial using one approved product reference and its actual packaging. It gives the sender a concrete way to report a label or item mismatch before more stock moves.
Prepare a labelled stock trial