POSTNET-9 Barcode Generator

What is POSTNET?

The United States Postal Service (USPS) uses POSTNET (Postal Numeric Encoding Technique) to direct mails. POSTNET codes are pasted on mail packets in the form of POSTNET Barcodes. These linear barcodes can be easily scanned using digital scanners. As a result the POSTNET Barcodes help in speeding up sorting and directing mails to correct destination.

What is POSTNET-9?

POSTNET Codes can be 5, 9 or 11 digits long. The nine digit long POSTNET code is called POSTNET-9. This is also called "C" code. It contains the ZIP code and four more digits. POSTNET-9 barcode contains 52 bars in total.

Calculation of Checkdigit of POSTNET

POSTNET uses a sum modulo-10 based checkdigit. All the digits in POSTNET code are added together and the sum is divided by 10. The remainder is then subtracted from 10 to get the checkdigit. For example:

Let's assume a sample code 12345-1234

The sum of all the digits in the code is 25

Dividing the sum by 10 gives us the remainder 5

Subtracting remainder from 10 gets us the checkdigit 5