UPC-E is a variant of the UPC (Universal Product Code), more compact than the more-common UPC-A. It is only able to encode a subset of the codes used in UPCs, being limited to ranges of code numbers that have sections which can be omitted (e.g., extra zeroes). There are apparently also UPC-B, UPC-C, and UPC-D versions as well, but they are not often mentioned and may not be in current use.
An optional additional bar code to the right of the UPC bar code encodes a supplemental 2 or 5 digits, used primarily on books and magazines. On magazines this encodes the issue number (the main bar code only encodes the periodical series) allowing issue-by-issue inventory tracking, while books use a supplemental code to indicate the suggested retail price.
- Review of barcode scanner apps
- iOS app to read UPC/EAN codes and find product info/prices
- Android app to read UPC and QR codes to look up product info/prices and other info coded or linked in bar codes
- Bar Code app (iOS)
Developer libraries and modules
- ZBar bar code reader library: cross-platform
- zxing (Zebra Crossing) (barcode library for Java, ported to some other systems)
- MediaWiki extension to generate UPC, EAN, and Code39 codes
- Global UPC database
- Another UPC search site
- UPC-E bar code generator
- Online barcode generator (supports many different formats)