A UPS tracking number,  usually start with "1Z" followed by a 6 character shipper number (numbers and letters), a 2 digit service level indicator, and finally 8 digits identifying the package, for a total of18 characters.

"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    

UPS tracking number format

• 1Z xxx xxx yy zzzz zzz c

• 10 digits

• 12 digits

• 9 digits

• H + 10 digits

• V + 10 digits

• 18 digits
  

UPS tracking number example

234918751
1Z662F416878787827
1Z001985YW96579840
1Z001985YW99744790
1Z001985YW90838348
1Z001985YW92164287
1ZE8889W0442766202