Frequently Asked Questions (FAQ) for TrackMyMail

Find the answers to frequently asked questions about TrackMyMail.
Products affected: TrackMyMail™


What is Stop-the-Clock?

Stop-the-Clock is a category of USPS operation codes. The criteria for a Stop-the-Clock scan is that if a mailpiece passes through one of these Stop-the-Clock sort operations before 10:00 AM, it is according the USPS confirm program "nearly certain that it will be delivered by the carrier that same day". When a mailpiece receives this type of scan TrackMyMail will report the piece with an estimated in-home delivery day.


How does TrackMyMail determine the In-Home date of the mailpiece?

The Estimated In-Home projection is based on:

  • The type of mail (letters vs. flats, standard vs. First-Class, etc.)
  • The time and date of the scan by the postal service
  • The type of scan

Based on those factors, we determine if the scan is a last scan (Stop-the-Clock) and we can estimate when the mailpiece will be in-home. IMB scans are assigned an operations code that relates to different levels of sort operations the postal service performs. This is where we see the Stop-the-Clock codes that the postal service recognizes as a code that indicates same-day delivery. The scans posted on our website are the most recent last scan or Stop-the-Clock scan. A Stop-the-Clock scan occurs for a mailpiece when it goes through any one of the sort operations that predict same-day delivery with a high level of certainty.

Our system uses an algorithm that incorporates all of the Stop-the-Clock operations codes, the time that the mailpiece was scanned, and the type and class of mail to determine an estimated in-home date which is then posted on the website. The initial scans for a mailpiece can be viewed by either downloading the USPS raw data or by using our Mail Piece History report which provides the first scan information.


If you need further assistance, please contact us.

UPDATED: March 11, 2022