Alex Pennace
May 10, 2007

Notes on UPS Tracking Numbers

There are several styles of UPS tracking numbers.

The "1Z" Style

"1Z" tracking numbers are of the form 1Z xxx xxx yy zzzz zzz c, where xxx xxx is the alphanumeric account number of the shipper, yy is the service code, zzzz zzz is the package identifier, and c is a checksum of some sort. "mike" has worked out the checksum, and has a tool online to check it.

A non-exhaustive list of service codes:

01	UPS United States Next Day Air ("Red")
02	UPS United States Second Day Air ("Blue")
03	UPS United States Ground
12	UPS United States Third Day Select
13	UPS United States Next Day Air Saver ("Red Saver")
15	UPS United States Next Day Air Early A.M.
22	UPS United States Ground - Returns Plus - Three Pickup Attempts
32	UPS United States Next Day Air Early A.M. - COD
33	UPS United States Next Day Air Early A.M. - Saturday Delivery, COD
41	UPS United States Next Day Air Early A.M. - Saturday Delivery
42	UPS United States Ground - Signature Required
44	UPS United States Next Day Air - Saturday Delivery
66	UPS United States Worldwide Express
72	UPS United States Ground - Collect on Delivery
78	UPS United States Ground - Returns Plus - One Pickup Attempt
90	UPS United States Ground - Returns - UPS Prints and Mails Label
A0	UPS United States Next Day Air Early A.M. - Adult Signature Required
A1	UPS United States Next Day Air Early A.M. - Saturday Delivery, Adult Signature Required
A2	UPS United States Next Day Air - Adult Signature Required
A8	UPS United States Ground - Adult Signature Required
A9	UPS United States Next Day Air Early A.M. - Adult Signature Required, COD
AA	UPS United States Next Day Air Early A.M. - Saturday Delivery, Adult Signature Required, COD

Assignment

Internet shipping uses zzzz zzz beginning with 9. Other products use different assignment strategies: For example, UPS Online WorldShip uses zzzz zzz beginning with 4. Another product has been observed using zzzz zzz beginning with 1.

UPS Online WorldShip, and perhaps other products, poll UPS's servers for an available block of tracking numbers. In the case of UPS Online WorldShip, it grabs a 300,000 number block.

As of 2006, UPS Online WorldShip will generate a tracking number based on a transformation of the previous tacking number, akin to sequential generation. Other products may also employ a non-random method of generating tacking numbers.

In May 2007, Barnes and Noble shipped at least four packages that reused tracking numbers from the previous month. It is possible that a system crash caused their shipping system to reissue tracking numbers.