GTIN formats
| Format | Digits | Used for |
|---|---|---|
| GTIN-8 (EAN-8) | 8 | Very small retail packages |
| GTIN-12 (UPC-A) | 12 | Retail products, mainly US and Canada |
| GTIN-13 (EAN-13) | 13 | Retail products worldwide, books (ISBN-13) |
| GTIN-14 | 14 | Cases and cartons (printed as ITF-14) |
The last digit of every GTIN is a check digit calculated from the others. It catches typos: a single wrong digit or two swapped neighbouring digits almost always produce a different check digit.
The check digit algorithm (GS1 mod 10)
- Take the number without its last digit.
- From the right, multiply the digits by 3, 1, 3, 1…
- Add the results.
- Check digit = (10 − (sum mod 10)) mod 10.
Example: for the UPC body 03600029145 the weighted sum is 58, so the check digit is 2: 036000291452.
Before you upload GTINs
Marketplaces and Google Merchant Center validate GTINs automatically, and a bad one can get a product disapproved. Paste your list into Bulk validate to find wrong check digits and bad lengths, and download the corrected CSV. In WooCommerce the number goes in the product’s GTIN, UPC, EAN or ISBN field under Inventory.
Need the barcode image? Use the barcode generator — EAN-13 or UPC-A for retail units, ITF-14 for cartons.
Restricted and special prefixes
- 2xx (EAN) and 02/04 (UPC) — restricted circulation: in-store codes for weighed or price-embedded items. Not valid for marketplaces.
- 978 / 979 — books (ISBN). 977 — periodicals (ISSN).
- 05, 99 — coupons.