My UPC or EAN is not working.

Why does my UPC have 13 digits?
Why is my EAN 1 digit too short?
Can I create a Walmart listing with an EAN and no UPC?

If you have asked yourselves these questions, you've come to the right place! 

A UPC is a 12 digit product identification number, whereas an EAN is a 13 digit product identifier. UPC or Universal Product Code is used in the US and Canada where EAN, or European Article Number, is used globally. 

It is common for UPC to be expanded by a leading 0 to get to the 13 digits that make up the EAN. Marketplaces will accept the EAN as a product identifier but if they are based primarily in the US they will likely need the UPC or another common Product Identifiers. Namely ISBN, or GTIN.

Walmart, for example, will require you to have a UPC, ISBN, or GTIN in order to list on their platform. Listing Mirror will prompt you with an error if you attempt to list with just an EAN. 

This tool is handy in sorting out what could be wrong with your UPC. 
https://www.upczilla.com/upc-validity/