They look almost identical and scanners treat them the same way — because a UPC-A barcode is an EAN-13 with a leading zero.
| UPC-A | EAN-13 | |
|---|---|---|
| Digits | 12 | 13 |
| Mainly used in | USA & Canada | Rest of the world |
| Structure | Number system + manufacturer + product + check | Country prefix + manufacturer/product + check |
| Relationship | Prefix a UPC-A with 0 and you have the matching EAN-13. | |
Because a UPC-A maps to the EAN-13 range 000–139 (USA & Canada), EAN-13 systems file US products under that prefix. On barcode.monster you can look up either format — enter a 12-digit UPC or a 13-digit EAN and you'll get the same product.
EAN-8 is an 8-digit code for products too small for a full barcode. It has its own GS1 prefix range and a check digit, but no room for a manufacturer block.