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USPS POSTNET (Zip, Zip+4, DPBC)

The postal barcode is used by the United States Postal Service to help sort business reply and courtesy reply mail. It is also used for regular bulk mailings. By using the postal code on your envelopes, you can significantly reduce the amount of postage on the items you mail.

The postal barcode may represent a five-digit zip code, a nine-digit Zip + 4 code, or an eleven-digit delivery point barcode. Of these three, you will realize the most significant savings on your postage if you use the eleven-digit delivery point barcode. This code, often called the DPBC barcode for short, was developed by the postal service to uniquely identify each of 115 million delivery points in the United States. It forms the system foundation for virtually eliminating the time used by carriers to sort letter mail prior to delivery.

You can use this application when producing camera-ready artwork of a single address that will be printed many times (for example, on business reply envelopes) to print the barcode. It can also easily be integrated with your ODBC database software when performing bulk mailings to a variety of different addresses, in order to perform the barcode translations for each different zip code "on the fly."

ClosedThe Character Set

The postal barcode character set contains the ten digits 0-9, the same characters that appear in United States zip codes.

ClosedThe Density

Unlike the other barcode symbologies, which are valid in a variety of different densities, the US Postal Service has specified a very precise density range for the postal symbology.

The proper density for a postal barcode is 21 bars per inch, plus or minus 1 bar. Another way of specifying this same value is to say that each bar/space pair must be between 0.045" and 0.050". This comes out to about 4 characters per inch.

ClosedThe Symbology Structure

Unlike the other barcode symbologies, which vary the width of the bars and spaces to encode the data, the postal symbology encodes data by varying the height of the bars in the barcode. All of the bars are the same width, and all of the spaces are the same width. In addition, the bars and spaces are fairly close in size to each other. The bars and spaces in a postal barcode tend to look like they are made up of the narrow bars and spaces of the other symbologies. The notable difference is the two different bar heights seen in the symbology.

Each postal barcode character contains 5 bars. For each of these five bars, two are tall and three are short.

ClosedHeight and Width of Bars and Spaces

The correct heights for the postal barcode bars are defined as follows:

The correct widths of the postal barcode bars and spaces are defined as follows:

ClosedThe Start and Stop Bars

The start of a postal barcode is indicated with a single tall bar at the beginning of the barcode. The end of the barcode is also indicated with a single tall bar.

ClosedCorrect Position of the Postal Barcode

The scanners used by the postal service to read postal barcodes are designed to look for the barcode in a particular area of your envelope. Therefore, if you do not position the barcode properly, the scanner may have trouble reading it.

The correct horizontal position of the barcode is specified as follows:

The correct vertical position of the barcode is specified as follows:

ClosedInput Data Considerations

The additional digit in each of these barcodes is a check digit that is used for the detection of errors in the scanning process. This digit is generated automatically. Therefore:

If you specify 11 digits in your zip code, your barcode will be 12 digits long.

If you specify 9 digits in your zip code, your barcode will be 10 digits long.

If you specify 5 digits in your zip code, your barcode will be 6 digits long.

If you fail to provide exactly 5, 9, or 11 digits in your zip code data, the data will adjust to the length of one of the above numbers. This results in a barcode that contains different data than you intended.