Is the hyphen in a ZIP Code number required?

The hyphen in a ZIP Code, specifically when referring to ZIP+4 codes, is used to separate the standard 5-digit ZIP Code from the additional 4 digits. The standard 5-digit ZIP Code identifies a specific delivery area or post office, while the extra 4 digits provide a more precise location within that area, such as a specific building or apartment.

While the hyphen helps to visually separate these two parts of the ZIP+4 Code, making it easier to read and understand, it is not strictly required for postal services to process the mail. The United States Postal Service (USPS) can recognize and sort mail based on both 5-digit and 9-digit ZIP Codes, with or without the hyphen. However, including the hyphen (as in 12345-6789) is a common convention that enhances clarity.

For most mail, the standard 5-digit ZIP Code is sufficient. The additional 4 digits (and the hyphen) come into play primarily for business mail or in areas where mail delivery routes are highly segmented. In these cases, the full ZIP+4 Code can expedite mail sorting and delivery by providing additional information about the recipient’s exact location.