To easily locate a nine-digit ZIP code, visit USPS.com and use the Look Up a ZIP Code tool to search for the desired address. This tool’s URL can be found in the menu of Quick Tools on the left.
Click the Quick Tools link on USPS.com, then click the ZIP Code Lookup link. Enter the desired street address, city, and state, then click Find. A list of addresses that match shows with the ZIP+4 Code, which consists of the five-digit ZIP code plus four additional, optional digits. A search for 11444 Vance Jackson in San Antonio, TX, for instance, returns search results that include the nine-digit ZIP code (“11444 Vance Jackson, San Antonio, 78230-1712”). If there are multiple mailboxes at an address, the search returns multiple ZIP+4 codes for the same address. Additionally, the website supports searches by firm, city, and state. However, it is best to search using the complete street address, as ZIP+4 codes do not appear for businesses with several locations. According to the U.S. Postal Service, using the ZIP+4 Code reduces the number of handlings a piece of mail undergoes and the opportunity for errors and misdelivery.