What Is a GTIN? GTIN-8, 12, 13 and 14 Explained
A GTIN (Global Trade Item Number) is the unique number that identifies a product in the GS1 system. A UPC is a 12-digit GTIN, an EAN is usually a 13-digit one, and a carton barcode carries a 14-digit one. The barcode is just a printed form of the number.
The four GTIN lengths
| GTIN | Digits | Printed as | Typical use |
|---|---|---|---|
| GTIN-8 | 8 | EAN-8 | Very small packages |
| GTIN-12 | 12 | UPC-A | Retail in the US and Canada |
| GTIN-13 | 13 | EAN-13 | Retail worldwide, ISBN books |
| GTIN-14 | 14 | ITF-14 or GS1-128 | Cases, cartons and pallets |
All four end in a check digit calculated with the same mod-10 method, so scanners can catch a misread. The remaining digits identify the company and the product.
How the lengths relate
GTINs are designed to fit into the same 14-digit field in a computer system. Shorter numbers are padded with leading zeros on the left. A UPC-A is therefore the same as an EAN-13 with a zero in front, and both can be stored as 14 digits with extra zeros. This padding is why one product is identified identically whether a scanner reports it with 12, 13 or 14 digits.
A GTIN-14 adds one thing: the first digit is a packaging indicator. If a single bottle has the GTIN-13 4006381333931, a case of 12 bottles might get a GTIN-14 that starts with indicator 1 and then uses the first 12 digits of the bottle's GTIN. The check digit is recalculated for the new number. This lets a warehouse tell the case from the single unit while still tracing it to the same product. The case rarely uses the same barcode as the bottle.
GTIN vs UPC vs EAN vs barcode
- GTIN is the identifier, the number itself.
- UPC and EAN are the names of the barcode symbols that carry a GTIN-12 and GTIN-13.
- Barcode is the picture, which could also be a QR code or GS1-128 holding the same GTIN.
So "I need a GTIN" and "I need a UPC" overlap, but not exactly. Marketplaces often ask for a GTIN and accept any of the valid lengths.
Where GTINs come from
GTINs are created from a GS1 company prefix. You buy a prefix (or individual numbers) from GS1, then add your own item numbers and a check digit. GS1 keeps a global registry that retailers and marketplaces can query, so the number must really belong to your company. See the GS1 US site for current fees and how to apply.
Where GTINs are used
- Marketplaces: Amazon, Google Shopping and Walmart match your listing to a catalog item by GTIN.
- Retail: the scanner reads the GTIN at checkout.
- Supply chain: GTIN-14 and GS1-128 labels track cases through distribution.
- Healthcare: medical device and drug labels carry GTINs, often in Data Matrix codes.
Creating a barcode from a GTIN
To print a GTIN as a barcode, choose the matching symbol. For 12 digits use the UPC barcode generator. For 13 digits use the EAN-13 generator. For 14-digit case numbers use the ITF-14 generator. Enter one digit less than the full length and the tool calculates the check digit; enter the full number and it verifies it. Barcode Ready runs in your browser and does not upload anything you type.
Common mistakes
- Using a number copied from another product. It will match a different catalog entry.
- Dropping the leading zero in a spreadsheet. Format the column as text.
- Reusing one GTIN for different sizes or colors. Each variant needs its own.
- Typing a GTIN with a wrong check digit. Always validate before printing.