ZIP + 4® Product

The ZIP + 4® Product is a base reference file that can be accessed by an application to assign the correct ZIP + 4® Code associated with a physical address.

Who is ZIP + 4® Product for?

ZIP + 4® is for mailers looking to add ZIP + 4® codes to their address files. Mailers must purchase or develop their own matching software in order to use this file.

First Class Mail

First Class Mail





Standard Mail

Standard Mail

Software Developer

Software Developer


What is ZIP + 4® Product?

The ZIP + 4® Product File enables businesses with computer capabilities to add ZIP + 4® codes to their address files. The ZIP + 4® file contains approximately 30 million records is available in its entirety or by selected states. The ZIP + 4® product contains raw data and does not contain any software. ZIP + 4® file is available through Electronic Product Fulfillment (EPF) on a monthly basis. The changed ZIP + 4® Code information is available monthly. 

To convert mailing lists to ZIP + 4®, mailers can:

  • Order an electronic ZIP + 4® database from the United States Postal Service® and develop their own address-matching software.
  • Lease or purchase software from an outside vendor and convert their own lists.
  • Subcontract their conversion through a service bureau.

Featured Resources

User Guides
Address Information System (AIS) Viewer User Guide

User guide for Address Information System (AIS) Viewer, an application that provides the ability to retrieve, view, and print reports on demand at a 5-digit ZIP code level.

Data Files
Sample ZIP + 4® File TXT

This document provides a sample of a ZIP + 4 .txt file.

Data Files
Sample ZIP + 4® Transaction File TXT

This document provides a sample of a ZIP + 4 Transaction .txt file.

Tech Guides
Address Information System (AIS) Products Technical Guide

The Address Information System (AIS) Products Technical Guide contains documentation on all AIS products, including Residential Delivery Indicator (RDI), Z4Change, ZIPMove, Zip+4, Five-Digit Zip Product, eLOT, Carrier Route Product, City State Product, and Delivery Statistics Product.

Applications/ Forms
Address Information System (AIS) Viewer Order Form (PS Form 5111)

Product order form for Adress Information System (AIS) Viewer. Products available for purchase are the City/State Delivery Type Retrieval, County Name Retrieval, Delivery Statistics Retrieval, and ZIP + 4 Retrieval.

Fact Sheets
Address Information System (AIS) Products Pricing

Pricing guide for Address Information System (AIS) products, including Carrier Route, ZIP+4, Five-Digit ZIP, City State, Delivery Statistics, Z4Change, ZIPMove, eLOT, and RDI.

Applications/ Forms
Electronic Product Fulfillment (EPF) Web Access Request Form

This form is used to create a Web-based account with the National Customer Support Center (NCSC) which will be utilized to retrieve/download files from the Electronic Product Fulfillment (EPF) website.

Applications/ Forms

Related Products

Address Information System (AIS) Viewer

AIS Viewer is an interactive application designed to provide the ability to retrieve, view, and print accurate and current ZIP Code™ information for all 50 states.

Carrier Route Product

The Carrier Route Product provides reference information needed to apply carrier route codes to addresses for presort postage discounts.

City State Product

The City State Product is a comprehensive list of city, county, and Post Office names associated with each ZIP Code™.

Delivery Statistics Product

The Delivery Statistics Product defines the number of post office boxes and business/residential deliveries on city, rural, and highway contract routes for every ZIP Code™ in the United States.

Enhanced Line of Travel (eLOT®)

The eLOT product allows mailers the ability to sort their mailings in approximate carrier-casing sequence.

Five-Digit ZIP® Product

The Five-Digit ZIP® Product provides five-digit ZIP Code™ data that can be appended to computerized mailing lists via address-matching software.

Z4Change Product

Z4Change Product provides mailers the information necessary to create an application that would facilitate frequent and cost-effective processing for updating very large computerized mailing lists for automation compatibility and improved deliverability.

ZIPMove Product

ZIPMove Product offers a means of correcting addresses that have undergone a ZIP Code™ realignment in which a change in city name and finance number occurred.



For more information about AIS Viewer and other addressing tools, contact the National Customer Support Center at 800-238-3150 Call: 800-238-3150, or at