Barcodes and GTINs for Knitwear: What Retailers Actually Require
Quick answer
Every sellable variation needs its own GTIN: each style, in each colourway, in each size. For apparel sold in Europe that is an EAN-13, in North America a UPC-A, and both are derived from a company prefix you license from GS1 in your own country — not from a reseller, and not from your factory. The factory's job is to print the barcode you supply at the right size, on the right label, with a scannable symbol; your job is to own the numbers and send them early enough to be printed.
Barcoding is the least glamorous part of a knitwear order and one of the most reliable sources of chargebacks. We see it constantly: a first wholesale order arrives at a retailer's distribution centre, half the labels will not scan at the receiving dock, and the deduction lands weeks later. Almost none of that is a manufacturing problem. It is a data problem, and it is entirely avoidable if the numbers are settled before the labels go to print.
GTIN, barcode and SKU are three different things
They get used interchangeably, which is where the confusion starts:
- GTIN — the number. Global Trade Item Number, usually 13 digits (GTIN-13 / EAN-13) or 12 digits (GTIN-12 / UPC-A). It identifies a product globally and belongs to whoever licensed the prefix.
- Barcode — the printed symbol that encodes the GTIN, so a scanner can read it. Same number, many possible symbols.
- SKU — your internal code. Yours alone, meaningless outside your business, and not a substitute for a GTIN when a retailer asks for one.
A retailer's system reads the barcode, looks up the GTIN, and matches it to the purchase order. If the number is not in their system, or is in it under a different product, the carton stops moving.
How many GTINs does a knitwear range need?
This is the question that catches first-time wholesale buyers. The rule is one GTIN per sellable unit variation, which in practice means one per style × colour × size.
- Style level is not enough. A sweater in four colours and five sizes is twenty GTINs, not one.
- Packs need their own. A two-pack of beanies sold as a single unit needs a GTIN distinct from the single beanie, even though the physical contents are the same.
- Size naming matters. If the retailer's system expects S/M/L and your labels say 1/2/3, the receiving clerk has no way to reconcile it. Our notes on size naming cover how to align that before production, not after.
Practically, this means allocating GTINs is a range-planning task. Allocate them when you build the line sheet, not when the goods are packed.
Where the numbers come from — and where they must not
GTINs are licensed from GS1, a national member organisation per country. You join GS1 in your own market, receive a company prefix, and allocate numbers under it. The prefix is what makes the number globally unique, and it is registered to your company name.
Two warnings worth stating plainly:
- Do not buy barcodes from resellers. Second-hand GS1 prefixes are sold cheaply online. They usually trace back to a company that let its membership lapse, and the number is registered to that company's name, not yours. Increasingly, retailer systems and marketplaces check the GS1 registry and reject the number.
- Do not let the factory assign numbers. If a factory allocates a GTIN for you, it belongs to them. Change supplier next season and your numbers go with them — and any retailer listing built on those numbers breaks.
GS1 membership costs vary by country and by company turnover, from a few hundred to a few thousand currency units a year. Compared with a single chargeback or a delisting, it is not the line item to economise on.
What the factory needs from you, and by when
Once you own the numbers, this is a straightforward handover:
- A GTIN list mapped to SKUs. One row per style-colour-size, with the number, the size name and the colour name as they will appear on the label.
- The label artwork or specification. Where the barcode sits, what else is on the label (fibre content, care symbols, country of origin, RN or CA number for the US), and the label size. Our guides to care labelling rules and trims, labels and hangtags cover what else shares that space.
- Enough lead time to print. Woven and printed labels have their own production cycle, typically one to two weeks plus shipping. Labels are the single most common cause of a packing delay, because everything else can be finished while they are still in transit.
Send the numbers with the purchase order. Not "before packing" — with the order, so the label plate is made while the yarn is being knitted.
Print quality: the part that actually fails
A correct number printed badly is an unscannable label. Barcode symbols are graded on ISO verification — typically A to F, with most retailers requiring a C or better at the point of receipt. The things that push a grade down:
- Wrong X-dimension — the bars printed too narrow. Common when a barcode is squeezed onto a small label or shrunk to fit a layout.
- Insufficient quiet zone — the clear margin on either side of the symbol. Text, stitching or a label edge crowding it will break scanning.
- Low contrast — grey bars on cream, or anything printed on a textured or ribbed surface that distorts the symbol.
- Printing across a curve or seam. A barcode that wraps around a hangtag fold or sits over a seam reads inconsistently.
Ask for a verification report, or scan a sample yourself with a checker app before bulk packing. It takes two minutes and it is the difference between a clean delivery and a deduction.
Selling online instead: marketplaces have their own rules
Amazon, and most large marketplaces, require a valid GTIN and will check it against the GS1 registry. If you genuinely have no brand-registered GTIN — common for handmade, private label or small-batch production — the correct route is a formal GTIN exemption, not an invented number. Shopify and your own web store have no such requirement, but if you plan to wholesale later, allocating real GTINs from the start saves relabelling the whole range. Our notes on selling knitwear on Amazon and Shopify go deeper on listing requirements.
One thing that is not a replacement: QR codes. They are useful for consumer engagement and increasingly for digital product information, but they are not a point-of-sale barcode and no receiving dock scans them.
How we handle it at YZR Sweaters
We work with certified partner factories (BSCI, SEDEX, Oeko-Tex) across Dongguan, and we treat barcode data the same way we treat measurements: as part of the specification, confirmed before production rather than discovered at packing. In practice that means we ask for your GTIN list when you place the order, we confirm the label layout against your artwork, we scan-check a label sample before the bulk run, and we send a photo of the finished label on the garment with the pre-shipment inspection so you can see it on the actual product. If you are supplying into a retailer with a vendor compliance manual, send it with the enquiry — the barcode, carton marking and EDI requirements are usually all in there, and they are far cheaper to meet at order stage than to fix on finished goods.
Preparing a wholesale order that has to scan at the receiving dock? Send us your GTIN list or tell us how many SKUs you need, and we'll confirm the label set, the print specification and the lead time.
Get a free quote Browse our knitwear rangeFrequently asked questions
Can the factory provide the barcode numbers for me?
We would advise against it. A GTIN is registered to the company that licensed the GS1 prefix, so a number a factory allocates belongs to that factory, not to your brand. If you change supplier, your numbers do not move with you, and any retailer listing built on them breaks. Licence your own prefix and send us the numbers.
Do I need a different barcode for every size?
Yes. A GTIN identifies one sellable unit, so each style-colour-size combination needs its own number. A sweater in four colours and five sizes is twenty GTINs. Multipacks need their own number as well, separate from the single item inside.
EAN-13 or UPC-A — which do I need?
It follows your selling market: EAN-13 is standard in Europe and most of the world, UPC-A in the United States and Canada. If you sell in both, allocate EAN-13 numbers and let the North American system read them — most scanners handle both, whereas a 12-digit UPC does not always work the other way. Confirm with the retailer if they specify one.
What happens if the barcode will not scan on delivery?
The carton cannot be received against the purchase order, which usually means manual handling charges, a relabelling fee or a chargeback deducted from your invoice. The cost of a verification-grade check on a label sample before bulk packing is a few minutes; the cost of discovering it at the distribution centre is deducted from the order.