Your First Product Identifier: GTIN, SKU, Barcode, EAN and UPC
Do you need a barcode or GTIN for a new product? Separate SKU, GTIN, EAN, UPC and the barcode carrier, then follow the right first-identifier sequence.
Jump around this page
- In 60 seconds
- 1. Are you making the product or reselling someone else's?
- 2. SKU and GTIN solve different problems
- 3. GTIN, EAN, UPC and barcode are not one word
- 4. If a retailer, marketplace or buyer says "you need a barcode", ask one more question
- 5. If you need a GTIN, use the issuer route deliberately
- 6. Choose the carrier after the identity
- 7. What about a Digital Product Passport?
- Your first-identifier decision
- What this page deliberately does not own
- Next useful question
- Sources
In 60 seconds
Do not start by buying or printing a barcode. Start by asking what is already identifying the product and who owns that identity.
- A SKU is an internal code your business controls. A GTIN is a shared trade-item identifier assigned under GS1 rules.
- A reseller should preserve the existing identifier from the brand owner or manufacturer rather than create a duplicate.
- There is no universal rule saying every product business must have a GTIN, barcode, QR Code or GS1 Digital Link.
- In a documented eMAG case, weak validation exposed 80,000 products carrying the same bogus GTIN and 200,000 additional identifier conflicts.
- ESPR separates the unique product identifier from the data carrier. The product-specific rule decides the detail for a DPP.
Use this sequence:
- If you are reselling an already identified product, preserve the manufacturer or brand owner's existing trade-item identifier. Do not create a duplicate by default.
- If you only need a code inside your own business, create or keep a stable SKU.
- If a retailer, marketplace, wholesaler or buyer needs a globally recognised trade-item identifier, establish exactly what they are asking for and who set the requirement.
- If a GTIN is needed, obtain and govern it through the appropriate GS1 issuing route rather than treating a random barcode number as equivalent.
- Only then decide how the identifier will be carried: linear barcode, QR Code, Data Matrix or another permitted carrier.
A SKU, GTIN and barcode are not the same thing. EAN and UPC are terms you will commonly see around GS1 GTINs and the retail barcodes that carry them. The durable technical definitions live on Product identifiers.
There is no universal rule saying every product business must have a GTIN, barcode, QR Code or GS1 Digital Link.
Source state: GS1 and ESPR source checks completed 7 September 2026.
1. Are you making the product or reselling someone else's?
This is the first fork: it decides whether you create identity or preserve it.
You are reselling or distributing an existing trade item
Use the identifier already assigned to that product where one exists.
GS1's current selling-online guidance tells resellers and distributors that marketplaces and retailers may ask for the product's existing GTIN and that the seller may need to obtain it from the brand owner or manufacturer.
That is the right default because a trade-item identifier is supposed to refer consistently to the same trade item. Creating a new GTIN merely because your business is new to the product can break that continuity.
Before creating anything, record:
- the existing identifier
- who assigned it
- which product or variant it identifies
- the source that proves the match
If the number is a GS1 GTIN, Verified by GS1 can help verify the company behind the identifier and, where available, product information.
You make or own-brand the product
Ask what kind of identity you need.
If you only need a stable internal reference for stock, operations or your own catalogue, an internal SKU can do that job.
If the product needs to be identified consistently across trading partners, retail systems or marketplaces, you may need a globally recognised trade-item identifier such as a GTIN. The exact requirement comes from the trading system, buyer or applicable rule you are trying to satisfy. It is not created by the fact that your business is small or new.
For the full identifier taxonomy and GTIN allocation rules, use Product identifiers.
2. SKU and GTIN solve different problems
A SKU is your internal stock or commercial code. You control its format and meaning inside your systems.
A GTIN is a globally recognised trade-item identifier in the GS1 system. GS1 describes it as the number used to uniquely identify a trade item that may be priced, ordered or invoiced in a supply chain.
The same product can have both:
| Identifier | Main job | Who controls it |
|---|---|---|
| SKU | Internal stock, catalogue or operational reference | Your business |
| GTIN | Shared trade-item identity in the GS1 system | Assigned under GS1 rules by the responsible brand owner or organisation |
Do not put an internal SKU into a field that is explicitly asking for a GTIN just because the form accepts digits.
3. GTIN, EAN, UPC and barcode are not one word
The first distinction:
- GTIN is the product identifier.
- EAN and UPC are common terms you will encounter for GTIN formats and the retail barcode implementations around them.
- Barcode is the machine-readable carrier or symbol that represents data, such as a GTIN.
A GTIN can be encoded in different barcode types depending on where and how it needs to be scanned. So choosing the number and choosing the printed carrier should be separate decisions.
For the durable definitions, use Product identifiers.
4. If a retailer, marketplace or buyer says "you need a barcode", ask one more question
Ask: what exactly is required, by whom and for what purpose?
The answer may be:
- a legal requirement under a product rule
- a standard used by the supply chain
- a marketplace listing rule
- a retailer or wholesaler trading requirement
- an internal system requirement
Those are different sources of authority.
A retailer or marketplace can make a commercial requirement a condition of trading without turning it into law. For the legal side, see does the GPSR require a GTIN. If the request came from a platform, use Marketplace requirements. If it came from a retailer or wholesaler, use What a retailer or wholesaler actually asks for.
Do not buy an identifier until you know which requirement you are satisfying.
5. If you need a GTIN, use the issuer route deliberately
For a UK business choosing the GS1 system, GS1 UK is the practical issuing route. Its current guidance describes GTINs as unique product identifiers and provides the membership route through which businesses manage numbers and barcode assets.
Before allocation, decide the product level you are identifying. A model, sellable variant, case, batch and individual item are not interchangeable identity levels.
Then keep a simple identity record:
| Governance field | What to record |
|---|---|
| Issuer or namespace | Who controls the identifier system |
| Identifier | The value itself |
| Product level | Model / variant / trade item / batch / item, as applicable |
| Identity owner | The business or brand responsible for assigning it |
| Evidence source | Issuer record, supplier record or controlled master data |
| Persistence rule | When the identifier must stay the same |
| Change rule | What kind of product change requires a new identifier |
This is the minimum governance to settle before the number is printed on packaging, pushed to a marketplace or embedded in a digital link.
An identifier field is not enough
A marketplace can collect an identifier and still have an identity problem. In a documented eMAG case, introducing GTIN collection without strong enough validation exposed 80,000 products carrying the same bogus GTIN and 200,000 additional identifier conflicts. That is a case study, not an industry prevalence estimate. It shows why the number must be correctly assigned, valid for the product, attached at the right granularity and mapped to the business's internal IDs.
GS1 UK's eMAG case study provides the evidence.
Once the identity is stable, the next question is where the facts attached to it should live. You do not automatically need a PIM, but you do need a governed product record. Continue to how to organise product data without a PIM.
6. Choose the carrier after the identity
The identifier is the identity. The barcode or 2D symbol is how machines read it.
That keeps three later decisions separate:
- Identifier: for example, a GTIN.
- Web syntax: for example, GS1 Digital Link where you have chosen the GS1 system and need a web-enabled identity.
- Physical carrier: for example, a linear barcode, QR Code or Data Matrix.
For GS1 Digital Link syntax and resolver questions, use GS1 Digital Link.
For the retail move towards 2D barcodes, use Ambition 2027. That programme is an industry transition goal, not a universal legal deadline.
Do not change a valid product identifier merely because you are changing the carrier that prints or encodes it.
7. What about a Digital Product Passport?
The EU Ecodesign for Sustainable Products Regulation separates the unique product identifier from the data carrier. It requires a DPP, where an applicable product-specific measure requires one, to be connected through a data carrier to a persistent unique product identifier.
The framework does not make "GTIN", "EAN", "UPC", "QR Code" or "GS1 Digital Link" the universal answer for every product category.
The applicable product rule decides the detail. Check the product-specific rule before choosing an identifier or carrier for a DPP.
Your first-identifier decision
Use this before you order labels or upload a catalogue.
| Question | If yes | If no |
|---|---|---|
| Is this an already identified product you are reselling? | Preserve and verify the existing identifier | Continue |
| Do you only need an internal stock reference? | Use a stable SKU | Continue |
| Has a trading partner asked for a GTIN/EAN/UPC/barcode? | Classify the source and exact requirement | Continue |
| Do you need a globally recognised GS1 trade-item identifier? | Use the appropriate GS1 issuing route | Do not create one without a reason |
| Is the identity fixed and governed? | Choose the carrier and digital architecture | Fix identity first |
If you cannot establish who assigned an existing identifier or what product it belongs to, keep the result as UNKNOWN until you can verify it. A confidently wrong identifier is worse than an explicit gap.
If you have already been given a number, you can check a number you have already been given in your browser before you build anything on it.
What this page deliberately does not own
This page does not replace the technical identifier dictionary, define GS1 Digital Link syntax, decide the 2D retail transition or catalogue every marketplace rule.
Its job is narrower: make the first identity decision in the right order, preserve existing identity where appropriate and stop commercial requests being mistaken for law.
Next useful question
Do I need only an internal SKU, or does this product need a shared trade-item identifier outside my business?
Sources
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EU law
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Standards body
Route-level claims were checked on 7 September 2026. Product-specific answers should be checked against the applicable legislation and current sector guidance rather than inferred from this page.
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