Benefits of ACS

Electronic and/or automated address correction has many benefits over manual address correction. A mailer who uses ACS can do the following:

ACS is designed to substantially reduce the number of address correction notices provided manually to mailers and replace them with electronic notifications. However, ACS does not currently and will not for the foreseeable future entirely eliminate manual address correction notices. Therefore, ACS is not a guaranteed service; the Postal Service makes no assurance that any minimum percentage of a mailer’s address correction notifications will be provided electronically rather than manually.

Note: If any discrepancy exists between this document (Publication 8) and Mailing Standards of the United States Postal Service, Domestic Mail Manual (DMM), the DMM always takes precedence. For the most current DMM, go to the Postal Explorer Web site ( and click on the links for Domestic Mail Manual (DMM). Any regulation in this publication can be amended or rescinded by notices in the Postal Bulletin, Federal Register, or the DMM. For further information, refer to the DMM, email the ACS Department at, or call the ACS Department at the National Customer Support Center toll free at 877-640-0724 (Option 1).

Note: The Postal Service encourages new and current ACS participants to sign up for a Fulfillment Service called SingleSource ACS. SingleSource ACS fulfillment removes the need for handling different file formats when dealing with Full Service ACS, OneCode ACS, IMpb ACS, and Traditional ACS. With SingleSource ACS, all of the ACS notices are combined into a single file format and are provided via Electronic Product Fulfillment (EPF). In addition to providing all ACS transactions in the same fulfillment format, it also provides detailed shipping notice data files and invoice data files that allow the customer to automate the reconciliation of fulfillment files. Participating in SingleSource ACS is as easy as selecting SingleSource ACS on the enrollment form. Information regarding SingleSource ACS is available at — scroll down to the section titled “ACS Technical Guides.”