Why there is always additional numbers on a zip code? Like 92115-588?

Question

Why there is always additional numbers on a zip code? Like 92115-588?

Answer 1

Yeah what the first answerer said. To scale it down, the post ofc uses it to pinpoint what post office gets the mail when it comes to the mail facility. He could have said just that!!

Answer 2

An extended ZIP + 4 code includes the five digits of the ZIP code, a hyphen and then four more digits, which allow a piece of mail to be directed to a more precise location than by the ZIP code alone.

A ZIP + 4 code uses the basic five-digit code plus an additional four digits to identify a geographic segment within the five-digit delivery area, such as a city block, a group of apartments, an individual high-volume receiver of mail or any other unit that could use an extra identifier to aid in efficient mail sorting and delivery. Use of the plus-four code is not required except for certain presorted mailings. In general, mail is read by a multiline optical character reader (MLOCR) that instantly determines the correct ZIP + 4 code from the address and — along with the even more specific delivery point — sprays a Postnet barcode on the face of the mailpiece that corresponds to 11 digits. This technology has greatly increased the speed and accuracy of mail delivery and, in turn, kept costs nearly constant for over a decade.

For post-office boxes, the general (but not invariable) rule is that each box has its own ZIP + 4 code. The add-on code is often one of the following: the last four digits of the box number (e.g., PO Box 58001, Washington DC 20037-8001), zero plus the last three digits of the box number (e.g., PO Box 12344, Chicago IL 60612-0344), or, if the box number consists of fewer than four digits, enough zeros added to the front of the box number to make it a four-digit number (e.g., PO Box 52, Garrett Park MD 20896-0052). However, there is no uniform rule, so the ZIP + 4 code must be looked up individually for each box.

It is common to use add-on code 9998 for mail addressed to the postmaster (to which requests for pictorial cancellations are usually addressed), 9999 for general delivery and other high-numbered add-on codes for business reply mail. For a unique ZIP code (explained below), the add-on code is typically 0001.

Answer 3

The ZIP + 4 Product File enables businesses with computer capabilities to add ZIP + 4 Codes to their address files. The ZIP + 4 file contains approximately 30 million records and is available in its entirety or by selected states. Mailers must purchase or develop their own matching software in order to use this file.

The ZIP + 4 file is available on cartridge or CD-ROM on a monthly or quarterly basis, and changed ZIP + 4 Code information is available monthly.

To convert mailing lists to ZIP + 4, mailers can:

order an electronic ZIP + 4 database from the United States Postal Service and develop their own address-matching software

lease or purchase software from an outside vendor and convert their own lists

subcontract their conversion through a service bureau

A sample ZIP + 4 file is available for download.

For more information, call the National Customer Support Center at 1-800-238-3150.