Errors in the ZIP + 4® Database?

Errors in the ZIP + 4 database (including typos or omissions, or incorrect, obsolete, poorly organized, or missing data) are the responsibility of Postal Service™ authorities.

If you spot any kind of error in the ZIP + 4 database, ask the local Post Office™ for that address to make the correction by having the postmaster submit form 1621 to their local Address Management Systems (AMS) office, otherwise the error is likely to continue appearing in future Postal Service database editions. A sample form 1621 is on page 40 of the March 1998 edition of the M-39 Handbook at the Postal Workers' Union archive.

Or, you can try contacting the AMS office directly. Use this form to locate the AMS office for the address in question.

Or, you can report data errors to the AMS support department at the National Customer Support Center at 800-331-5747 or via email.

The Postal Service does not list personal names in the ZIP + 4 database. Company names are listed when the organization has been assigned a unique ZIP + 4 code because of the volume of mail the company sends or receives.

The ZIP + 4 database is designed to validate addresses that receive mail. If a street address doesn't receive mail (for example, the recipient uses a Post Office box instead), then the Postal Service may be deliberately leaving the street address out of the database.

Any text displayed in lower case when it should be upper case, or vice versa, is not an error in the ZIP + 4 database. The Postal Service actually maintains all address records only as upper case text. Any lower case characters you see are simply generated by software that capitalizes only the first character in a word.


  • Go to the ZP4 home page.
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