What Is a GTIN? GTIN Numbers, EAN, UPC and MPN Explained

A GTIN (Global Trade Item Number) is the GS1 number that identifies a trade item worldwide. It is the set of digits printed under a retail barcode. EAN and UPC are not separate identifiers: GS1 says a GTIN-13 is also called an EAN and a GTIN-12 is also called a UPC. They are the same kind of number at two lengths.

What makes identifiers hard is everything around that fact: the number, the barcode that carries it, and how far the number may travel. This guide is for the person who decides which identifier goes in which feed column. Usually, that person has already had a listing rejected for a GTIN that looked valid.

What is a GTIN? The four GTIN formats

A GTIN comes in four data structures. The length tells you where it came from and what it usually identifies:

• GTIN-8: eight digits, for small items where a full barcode will not fit on the pack.
• GTIN-12: twelve digits, used mainly in North America. This is the number people call a UPC.
• GTIN-13: thirteen digits, used in Europe and most markets outside North America. This is the number people call an EAN (or JAN in Japan).
• GTIN-14: fourteen digits, used for cases and other packaging levels above the consumer unit.

Two habits cause most of the confusion. The first is calling the number "the barcode". The barcode is a symbol that carries the number; the GTIN is the number itself. The second is "EAN-14". The fourteen-digit number is a GTIN-14, and the barcode usually meant is an ITF-14, which is how Google Merchant Center lists multipack identifiers.

EAN vs GTIN and EAN vs UPC: the actual difference

EAN vs GTIN is not a real comparison. An EAN is one format of GTIN, the thirteen-digit one. Every EAN is a GTIN; not every GTIN is an EAN.

EAN vs UPC comes down to one digit and one region. GS1's prefix list notes that a twelve-digit GTIN has an implied leading zero. So a UPC sits inside a thirteen-digit field with a zero in front, and nothing about the number changes. The reverse does not work. A thirteen-digit EAN that starts with anything other than zero has no twelve-digit form. If a trading partner insists on twelve digits, get a GTIN-12 from GS1. Do not truncate the EAN and recalculate the check digit. That truncated number belongs to somebody else's product, or to nobody.

How a GTIN number is built

A GTIN is a GS1 company prefix, an item reference and a check digit. Unlike a classification such as ETIM or UNSPSC, it encodes nothing about what the product is.

• Company prefix. GS1 defines it as a string of four to twelve digits, usually issued by a GS1 member organisation such as GS1 UK. The shorter the prefix, the more item references are left for your products.
• Item reference. The digits the brand owner assigns, one per trade item.
• Check digit. The final digit, calculated from all the others.

One licence condition matters more than the rest. The GS1 General Specifications say a company prefix, or any key built from it, shall not be sold, leased or given for use by another company. That is why resold barcodes cause trouble later.

The leading digits do not show country of origin. GS1's support answer is a flat "No". They show which GS1 member organisation issued the number: GS1 UK numbers start 500 to 509, wherever the product is made. Quoting the prefix as a provenance claim on a product page is a compliance risk.

How to calculate a GTIN check digit: a worked example

One method works for every GTIN length and for the eighteen-digit SSCC. It runs right to left:

1. Start at the digit immediately to the left of the check digit.

2. Moving left, multiply the digits by 3, 1, 3, 1 and so on.

3. Add the results.

4. Subtract the total from the nearest equal or higher multiple of ten. The answer is the check digit.

GS1's own GTIN-13 example uses the first twelve digits 629104150021. Reading from the right, the digits and weights give 1x3, 2x1, 0x3, 0x1, 5x3, 1x1, 4x3, 0x1, 1x3, 9x1, 2x3 and 6x1. The products are 3, 2, 0, 0, 15, 1, 12, 0, 3, 9, 6 and 6, which sum to 57. The next multiple of ten is 60, so the check digit is 3. The full GTIN is 6291041500213.

Guidance that says "multiply the odd positions by three" is right for a GTIN-12 and wrong for a GTIN-13. Right to left, one function covers every length. It also means leading zeros add nothing to the sum, so padding a GTIN to fourteen digits never changes its check digit.

Storing GTINs: fourteen digits, held as text

GS1's EDI guidance is specific. GS1 recommends always storing a GTIN as a fourteen-digit number, with shorter formats filled with leading zeros. A GTIN-13 gains one zero, a GTIN-12 two and a GTIN-8 six.

Hold the field as text, not as a number. Excel strips leading zeros and shows long numbers in scientific notation. Microsoft documents Excel's number precision as 15 digits, so a fourteen-digit GTIN loses zeros but keeps its digits. An eighteen-digit SSCC is not so lucky: digits beyond the fifteenth are lost.

GTIN-14, cases and the indicator digit

A GTIN-14 identifies a grouping of identical items, such as a case of twelve. It is built from the base GTIN with an indicator digit in front and a new check digit at the end. GS1 Canada's guide gives this worked example:

1. Start with the GTIN-12 990497300014 and drop its check digit, leaving 99049730001.

2. Add a filler zero and the indicator digit 1 in front: 1099049730001.

3. Calculate a fresh check digit over those thirteen digits. It is 1.

4. The GTIN-14 is 10990497300011.

Carrying the old check digit forward is the bug that shows up most often. Position fourteen is the check digit for the whole new number.

Indicator digits 1 to 8 are used for groupings of identical items. GS1 Canada states there is no worldwide consensus on which number indicates which packaging level. Code that assumes "1 means inner, 2 means case" is inventing meaning that is not there. Indicator 9 is different: it marks a variable measure item. And since 1 January 2023, the GS1 General Specifications say a GTIN-8 shall not be used for groupings at all.

An SSCC is not a case GTIN. It is eighteen digits and identifies one specific pallet or parcel, so it never belongs in a GTIN field.

MPN, SKU, ASIN and ISBN: how they relate to a GTIN

MPN. A manufacturer part number identifies a product among one manufacturer's products. There is no central registry, so two unrelated manufacturers can use the same string. That is why channels ask for brand and MPN as a pair. Google accepts an MPN of 1 to 70 characters and says to use the manufacturer's MPN unless you are the manufacturer.

SKU. A stock keeping unit is your own internal code. It is not a GTIN and must not be sent where one is expected. Google's guidance on unique product identifiers says not to substitute an internal SKU. The dangerous case is a numeric SKU that happens to be twelve or thirteen digits long and passes a length check.

ASIN. Amazon describes an ASIN as ten letters and numbers that identify a product within its own catalogue. It means nothing outside Amazon.

ISBN and ISSN. These genuinely are GTIN-13s. GS1 allocates prefixes 978 and 979 to Bookland for ISBNs, and 977 to serial publications for ISSNs. Google asks for the thirteen-digit ISBN and says to convert any ten-digit ISBN.

Which GTIN goes where: Google, Amazon and trade feeds

Each destination has its own rules. These are the ones as documented by the channels themselves.

Google Merchant Center. GTIN is strongly recommended for products that are widely manufactured and have one. Accepted types are UPC (12 digits), EAN (13), JAN (8 or 13), ISBN (13) and ITF-14 (14). Google checks the check digit and rejects restricted prefixes 02, 04 and 2, and coupon prefixes 05, 98 and 99. A product that has a GTIN but is submitted without one may have limited visibility. Incorrect identifiers may get the product disapproved. Without a GTIN, Google wants brand and MPN together. The identifier_exists attribute set to false is only for products with no assigned identifiers, such as custom goods, handmade items and books published before 1970. There is more on getting a feed through validation in the guide to Google Merchant Center product data.

Amazon. Amazon's seller guidance names UPC, EAN, JAN and ISBN as the common product IDs, describing a GTIN as up to fourteen digits. Brands without a GTIN can apply for a GTIN exemption, with images showing all sides of the product and packaging. Amazon's policy, as quoted by GS1 UK, says it verifies product identifiers against the GS1 database. EANs and UPCs that do not match GS1's information are considered invalid. Amazon recommends getting identifiers directly from GS1. The Amazon listing optimisation guide covers the rest of the listing.

Wholesale and procurement feeds. GS1 XML defines the GTIN as exactly fourteen digits. B2B receivers usually want the GTIN alongside a classification: an ETIM class for technical wholesale, or UNSPSC codes for procurement systems. The identifier says which product; the classification says what kind of product. A standards mapping layer holds both against the same record.

Why a valid-looking GTIN gets rejected

There are four distinct failure modes, and each needs a different fix:

• Bad arithmetic. Wrong length or wrong check digit, usually from a spreadsheet stripping zeros or a typing slip. A format check catches it.
• Restricted circulation numbers. GS1 uses prefix 02 and 20 to 29 for restricted circulation numbers within a region, and 04 within a company. GS1's General Specifications state that RCNs are not GTINs. These are the numbers scales print in store and warehouses assign to own-label lines. They pass a check digit test and still fail as identifiers.
• Numbers licensed to someone else. Barcodes bought from resellers often trace back to the reseller's prefix, not yours. GS1 database checks then show another company as the licensee.
• The right format on the wrong product. A GTIN copied from a similar product or a previous variant. Google tells merchants not to guess or reuse values from similar products.

The first two can be caught automatically before a feed leaves the building. That is the job of GTIN and barcode validation run on every import, rather than at the channel's error report.

When a product needs a new GTIN

GS1's GTIN Management Standard, as summarised in GS1 UK's GTIN management handbook, starts with three questions. Is there a regulatory or liability disclosure requirement? Is there a substantial impact on the supply chain? Is a consumer or trading partner expected to tell the changed product apart from the old one? If any answer is yes, a new GTIN is likely. The ten rules then cover the common cases:

• A new product, a change to declared net content, or a change to the primary brand.
• A change of more than 20% in any dimension or in gross weight.
• A change to declared formulation, certification marks or a pre-printed price.
• A change in pack or case quantity, which needs a new GTIN only above the consumer unit.

On reuse, GS1 UK states that from January 2019 GTINs should never be reused, replacing the old 30 and 48 month waiting periods. There are two exceptions. A GTIN assigned to an item that was never produced may be reused 12 months after deletion from the catalogue. And a product withdrawn and reintroduced unchanged keeps its original GTIN.

What a GTIN costs in the UK

GS1 UK charges an annual licence fee based on company turnover, with new pricing from 1 April 2025. The lowest band is £50 a year for turnover under £100,000, with 10 GTIN-13s included. The highest is £4,250 a year for turnover over £1 billion, with 100,000 included. Other GS1 member organisations price differently, so "GS1 costs X" is never a global statement.

2D barcodes, GS1 Digital Link and the GTIN

The 2027 milestone is often described as the end of the linear barcode. It is not. GS1's 2D in retail guideline sets an initial goal for the end of 2027. By then, retail point of sale should be globally capable of reading the GTIN from both existing linear and 2D barcodes. GS1's American member organisation markets the programme as Sunrise 2027. The symbols in scope are GS1 DataMatrix, and Data Matrix or QR Code carrying a GS1 Digital Link URI.

In a Digital Link URI the GTIN sits after /01/, padded to fourteen digits. Digital Link carries the GTIN; it does not replace it. What 2D adds is room for batch, expiry and serial data, which has to exist and be correct before the carrier changes. The same discipline sits under all standards-based product data: formats change, the data quality requirement does not.

GTIN FAQs

What is a GTIN?

A GTIN, or Global Trade Item Number, is a number issued under the GS1 system that identifies a trade item worldwide. It comes in four lengths: GTIN-8, GTIN-12, GTIN-13 and GTIN-14. It is made of a GS1 company prefix, an item reference and a check digit. The number is usually printed under a barcode, but the GTIN is the number itself, not the barcode symbol that carries it.

What is the difference between EAN and GTIN?

An EAN is one format of GTIN. GS1 states that a GTIN-13 is also called an EAN, so every thirteen-digit EAN is a GTIN. GTIN is the umbrella term that also covers the eight, twelve and fourteen-digit formats. When a channel asks for a GTIN, a valid EAN-13 issued by GS1 satisfies it. When it asks specifically for an EAN, it wants the thirteen-digit form.

What is the difference between EAN and UPC?

A UPC is a twelve-digit GTIN-12, used mainly in North America. An EAN is a thirteen-digit GTIN-13, used in Europe and most other markets. A UPC can be written as a thirteen-digit number by adding a leading zero, and its check digit stays the same. An EAN that does not start with zero has no twelve-digit form, so a separate GTIN-12 is needed if a buyer demands one.

How do I get a GTIN number in the UK?

Join GS1 UK, which licenses a company prefix to your business and lets you create GTINs from it. Fees are annual and based on turnover, starting at £50 a year for businesses with turnover under £100,000, with 10 GTIN-13s included. Buying from GS1 directly matters because Amazon, among others, checks identifiers against the GS1 database and treats numbers that do not match as invalid.

Can I use a SKU instead of a GTIN?

No. A SKU is an internal code that you create yourself, and it means nothing outside your business. A GTIN is issued under a licensed GS1 prefix and is globally unique. Google tells merchants not to substitute an internal SKU for a GTIN. If a product genuinely has no GTIN, submit brand and MPN instead, or mark the product as having no identifiers where the channel allows it.

Does Google Merchant Center require a GTIN?

Google strongly recommends a GTIN for any product that is widely manufactured and has one. Products with an assigned GTIN submitted without it may have limited visibility, and incorrect identifiers can get products disapproved. Products without a GTIN should carry brand and MPN together. The identifier_exists attribute set to false is reserved for products that genuinely have no identifiers, such as custom or handmade goods.

How is a GTIN check digit calculated?

Start at the digit next to the check digit and move left, multiplying digits alternately by 3 and 1. Add the results, then subtract the total from the nearest equal or higher multiple of ten. For GS1's example 629104150021, the weighted sum is 57, so the check digit is 3. The same right-to-left method works for GTIN-8, GTIN-12, GTIN-13, GTIN-14 and SSCC.

Key takeaways

• A GTIN is the GS1 number that identifies a trade item. EAN is the thirteen-digit GTIN-13 and UPC is the twelve-digit GTIN-12.
• Store every GTIN as fourteen digits with leading zeros, in a text field. Padding never changes the check digit.
• Calculate check digits right to left with weights of 3 and 1. Left-to-right rules break between lengths.
• MPN, SKU and ASIN are not GTINs. Send brand plus MPN where no GTIN exists, and never send a SKU in a GTIN field.
• Restricted circulation numbers and reseller barcodes can pass a check digit test and still be rejected. Validate scope and licensee, not just arithmetic.
• A GTIN identifies a product; ETIM and UNSPSC classify it. B2B feeds usually need both on the same record.

See it in practice: validate GTINs and barcodes on every import, product data quality checks and marketplace syndication with the right identifier per channel.