What is the difference between EAN-13 and UPC-A?
EAN-13 is the 13-digit retail format used outside North America; UPC-A is its 12-digit counterpart used within it. Both require a GS1-issued number to be valid for resale. Generating one yourself encodes the number correctly but does not register it.
When should you use Code 128 instead?
Code 128 encodes any printable text, not just digits, and is the default choice for internal stock, asset tags and warehouse locations. It has no retail registration requirement because it isn’t a retail product identifier.
Once you know which format fits, generate it on the barcode generator, which also shows the smallest size each format held up at in our print-and-scan test. Full walkthrough: how to create a barcode.