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, 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 1983, includes the five digits of the ZIP code, a
hyphen, and four additional digits that determine a more specific location within a given ZIP code. The USPS provides a free [https://www.usps.com/zip4/ online lookup tool] for ZIP codes.