Look up address and ZIP codes on USPS.com by accessing the site's ZIP code search tool and entering the available information into the designated fields. The tool allows you to find the ZIP code associated with an address as well as the ZIP codes within a given city.
The United States Postal Service uses a system known as ZIP codes to organize and route mail to different regions of the country and avoid confusion of similar city names and street addresses. Find the ZIP code of an exact address by visiting USPS.com and clicking on the Look Up a ZIP Code button under the Quick Tools main menu option. On this page, enter in the street address and unit or apartment number along with the city and state in which the address exists. The tool returns the full address and ZIP code according to current United States Postal Service records.
If you are trying to look up the ZIP code of a business but don't have its address, enter in the business' name along with its city and state to conduct a search. Results include all known ZIP codes that match official business name registration records. The tool does not display addresses, but does label ZIP codes associated with a P.O. Box.