A barcode is a series of long and short bars that represent ZIP Codes, ZIP+4 codes, and delivery addresses. The Postal Service uses automated equipment that reads the barcode to process and sort mail. At the Postal Service, the barcode tells us where to deliver your mail.
There are different kinds of barcodes for different aspects of the mail, such as the purchase of extra services (like USPS Tracking or Registered Mail). You'll also notice that tray and sack labels have barcodes on them. All of these barcodes have different functions and must meet certain specifications so that the Postal Service can read them correctly.
A barcode by itself does not qualify a mailpiece for a lower price. To get lower postage prices, a mailpiece must have certain characteristics (such as an Intelligent Mail barcode (IMb) with a delivery point routing code). Click below to find out more.