encoded in EAN-13 barcode. EAN barcodes are used worldwide for
lookup at retail point of sale, but can also be used as numbers
for other purposes such as wholesale ordering or accounting.
The most commonly
used EAN standard is the thirteen-digit EAN-13, a superset of
the original 12-digit Universal Product Code (UPC-A) standard
developed in 1970 by George J. Laurer. An EAN-13 number
includes a 3-digit GS1 prefix (indicating country of
registration or special type of product). A prefix with a first
digit of "0" indicates a 12-digit UPC-A code follows. A prefix
with first two digits of "45" or "49" indicates a Japanese
Article Number (JAN) follows.
The less commonly
used 8-digit EAN-8 barcode was introduced for use on small
packages, where EAN-13 would be too large. 2-digit EAN-2 and
5-digit EAN-5 are supplemental barcodes, placed on the
right-hand side of EAN-13 or UPC. These are generally used for
periodicals like magazines or books, to indicate the
current year's issue number; and weighed products like food, to
indicate the manufacturer's suggested retail price.
The check digit
is an additional digit, used to verify that a barcode has been
scanned correctly. It is computed modulo 10, where the weights
in the checksum calculation alternate 3 and 1. In particular,
since the weights are relatively prime to 10, the EAN-13 system
will detect all single digit errors. It also recognizes 90% of
transposition errors (all cases, where the difference between
adjacent digits is not 5).