Do I need a different barcode for each size and colour?
Yes. Every version a customer can buy on its own needs its own number — and working that out before you apply to GS1 decides whether you buy one number or twelve.
A GTIN — the number behind an EAN-13 or a UPC — identifies a trade item: something priced, ordered, invoiced or scanned on its own. That is the whole rule, and the rest follows from it. A blue shirt in size S and the same shirt in size XL are ordered separately, counted separately and can be priced differently, so they are two trade items and take two numbers.
Sharing one number across variants looks like a saving and turns into a mess: the till charges whatever that single number is set to, stock counts merge two products into one, and an online listing cannot say which size is out of stock. Retailers refuse it for exactly those reasons.
What forces a new number
GS1’s GTIN Management Standard is specific about which changes require a new GTIN. These are the ones that catch small producers out:
| Change | New GTIN? |
|---|---|
| Size, colour, flavour — any version sold on its own | Yes |
| Declared net content, any change up or down | Yes |
| Dimensions or gross weight, more than 20% on any axis | Yes |
| Formulation or function, when the label declaration changes | Yes |
| Brand name or brand logo | Yes |
| Adding or removing a certification mark (organic, kosher…) | Yes |
| What goes inside a mixed pack or gift set | Yes |
| A price printed on the pack | Yes |
| How many units in a case or on a pallet | Yes — at case and pallet level, not the unit |
| A temporary promotional pack | Yes — at case and pallet level, not the unit |
| A marketing claim with no legal or price effect | No |
| A new batch or a new expiry date | No — that is data, not identity |
So how many numbers do I actually need?
Count the things a buyer can order on their own. Four colours in three sizes is twelve trade items and twelve GTINs, not one. Then add a number for each packaging level you ship: a case of twelve carries its own number, usually printed as an ITF-14, and a pallet carries an SSCC, which is a different kind of number again.
This is the arithmetic to do before you apply, because it decides what you buy: a single number licensed once, or a company prefix that covers a whole range.
Twelve variants without twelve afternoons
One row per variant in a spreadsheet, one label design, and the two get combined: the name, the size, the colour and the barcode of each row land in the same places on the label. Twelve rows print twelve different labels in one go, and the same file grows with you when the range does.