How To Read A Nixie Label

By Paul Johnson, President CMS – Complete Mailing Solutions

Nixie Labels- Mysterious Hieroglyphics or Useful Information?

In our series focusing on how to reduce returned mail, we thought it would be useful to unveil the mystery of how to read the yellow nixie label on returned mail pieces.

Nixie labels are chockful of information. Let’s start with getting acquainted with the USPS systems that generate these labels.

The Postal Service utilizes two systems for forwarding and redirecting mail. Each system will generate a Nixie label:Undelivered envelope with yellow sticker

  1. PARS=Postal Automated Redirection System
  2. CFS=Computerized Forwarding System
    • RFS=Remote Forwarding System (a subset of CFS)


The Postal Automated Redirection System (PARS) identifies and redirects forwardable, machinable letter mail during processing. It handles 2 categories of mail: Carrier Identified Forwards (CIF) and Return to Sender (RTS).
The Postal Service uses the Computerized Forwarding System (CFS) to handle mail that is non-machineable, including letters, flats and parcels. There are two categories that CFS handles: Forwards and Nixies (Return to Sender).
Very simply, these two systems sort and process the mail, which includes:

  • Identifying whether the letter, flat or parcel has a correct address and is mailable
  • If not, if there is a Change of Address (COA) on record and can be forwarded
  • Determining whether the mail piece is Undeliverable As Addressed (UAA)
  • If it is undeliverable, following directions given from the Ancillary Endorsements, i.e.:
    • Forward the mail piece and notifying the sender
    • Return the mail piece with new address information (via the Nixie label)
    • Destroy the mail piece
  • Complete processing and delivering the mail

The Nixie labels generated by these two systems provide valuable information to the sender regarding why the mail piece cannot be delivered. Some of the reasons mail is Undeliverable As Addressed (UAA) that are mentioned on the Nixie label include whether:

  • A new mailing address exists for the recipient (a Change of Address has been filed)
  • There is no forwarding address (often because the recipient did not fill out a Change Of Address (COA) with the Post Office
  • The Change of Address has expired (COA’s cover a one-year period)
  • There are errors in the address
    • Missing information
    • Incorrect information
  • The address does not exist (Address Unknown)
  • The location is vacant
  • A mail receptacle is not available

Additional details are listed on the label. The illustrations below identify the specific information that return labels contain for each of these two systems
(Click on each graphic for better visibility).

CFS RFS Nixie Label with arrows

Nixie labels are a valuable tool to keep your database up-to-date and ensure money is not spent on mail that will never reach the intended recipient. Ancillary Endorsements also play a helpful role. You can read more about Ancillary Endorsements in our earlier post: Ancillary endorsements – What are they? Why use them?
Contact us today for information on tools to reduce the number of Nixie labels you are receiving – 303-761-0681 or envelopes@cms-colorado.com