How to Use a ZIP Code Lookup

Learn the fastest ways to find a ZIP Code by city, county, state, or exact postal code.

A ZIP Code lookup helps you connect a postal code with the city, county, state, time zone, and other location details tied to that code.

If you already know the ZIP Code, search for the number directly to confirm the city and county. If you only know a city or county, search by that place name to see matching ZIP Codes.

For business use, ZIP Code lookup tools are helpful for shipping estimates, territory planning, address checks, and local market research.

ZIP codes are a system of postal codes used by the United States Postal Service (USPS) since 1963. The term ZIP, an acronym for Zone Improvement Plan, is properly written in capital letters and was chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the code in the postal address. The basic format consists of five decimal numerical digits. An extended ZIP+4 code, introduced in the 1980s, includes the five digits of the ZIP code, a hyphen, and four more digits that determine a more precise location than the ZIP code alone. The term ZIP code was originally registered as a servicemark (a type of trademark) by the U.S. Postal Service, but its registration has since expired.

ZIP codes designate only delivery points within the United States and its dependencies, as well as locations of its armed forces. There are no ZIP codes reserved for designating mail bound for foreign destinations (with the exception of U.S. military units stationed outside of the United States), and therefore, international outbound mail should not include a ZIP code in the delivery address. The last line of a foreign address must only show the name of the country of destination.