Expand Zip Code Attestation For Free

The first three digits of a ZIP Code together usually indicate the central mail processing facility, also referred to as a sec center or sectional center facility to which that ZIP Code belongs. This facility is the mail sorting and distribution center for a zone or area.

What is the four-digit extension? It represents a specific delivery route within that overall delivery area. For PO boxes, the four-digit extension usually includes the PO box number. Including the last four digits means mailings will arrive to their intended destination faster, as well as discounts on bulk mailings.

The 9 is for anywhere on the West Coast and the Pacific, including Guam and American Samoa. 900 to 961 are all located in California, for example.

These digits, in conjunction with the first digit, represent a Sectional Center Facility (SCF) or a mail processing facility area. These areas are serviced by the U.S. Post Office SCFs. Note that a single SCF often services multiple three-digit areas.

ZIP Codes are numbered with the first digit representing a certain group of U.S. states, the second and third digits together representing a region in that group (or perhaps a large city) and the fourth and fifth digits representing a group of delivery addresses within that region.

So what do the extra numbers mean? These last 4 digits represent specific delivery routes within delivery areas. This extra detail means an even more precise matching to a more granular level. It could represent a handful of houses on one side of a street, or even a single building that receives a high volume of mail.

So, USPS created 9-digit ZIP Codes to ensure fast and accurate mailings. They indicate the actual path the mail should travel and usually they narrow down to somewhere between ten to twenty homes.

These are just some of what makes the U.S. ZIP code system a fascinating rabbit hole to go down. Nope. You don't need to use the extra four-digit ZIP code. In fact, you don't need to use a ZIP code at all, but they help your mail get there a whole lot faster, so use them if you've got 'em.

Also called ?plus-four codes?, ?add-on codes?, or ?add-ons?, the ZIP+4 code starts with the standard five-digit ZIP Code. The four extra numbers are added after a hyphen to complete the ZIP+4. So what do the extra numbers mean? These last 4 digits represent specific delivery routes within delivery areas.

A United States postal code, for example, might be either five digits or five digits followed a hyphen (dash) and another four digits (12345-1234). If you are validating US postal codes, allow for both conditions. The following rule validates a field that can be five digits, five digits + dash + 4 digits, or blank.