How UPC-A relates to EAN-13
UPC-A is effectively a subset of EAN-13. A 12-digit UPC-A number becomes a valid EAN-13 number by adding a 0 in front, and the bars are the same, so checkout scanners around the world read both.
The UPC was developed in the early 1970s, with George Laurer at IBM credited with the symbol design, and the first retail scan took place in 1974 in Ohio. EAN-13 was created afterward as an international extension.
Digits and check digit
The 12 digits are a GS1 company prefix, an item reference and a check digit. The check digit uses weights of 3 and 1: multiply the digits in odd positions by 3, the digits in even positions by 1, add them, and round up to the next multiple of 10.
For example, 01234567890 gives a weighted sum of 85, so the check digit is 5 and the full code is 012345678905. UPC-E is a shorter, zero-suppressed form for small packages.
- Length: 12 digits
- Width: 95 modules plus quiet zones, like EAN-13
- Short form: UPC-E, 8 digits
- Numbers issued through GS1 US in the United States