Standard ZIP Code
The most common type of ZIP code, representing a geographic delivery area served by regular USPS mail carriers and associated with residential and business addresses.
Standard ZIP codes make up the vast majority of the roughly 41,700 active ZIP codes in the United States. They represent geographic areas where USPS mail carriers deliver to street addresses, and they contain a mix of residential, commercial, and institutional recipients.
The USPS classifies each standard ZIP code into a carrier route structure, with individual letter carriers assigned to specific routes within the ZIP. Each route serves a defined set of delivery points — mailboxes, apartment clusters, or business lobbies.
Standard ZIP codes are the type most commonly found in Census demographic data, real estate listings, marketing databases, and mapping applications. They have corresponding ZCTAs in Census products and are the codes most people encounter in daily life.