# How many possible UPS tracking numbers? **URL:** \ **Category:** Factual Questions\ **Created:** [December 31, 2016, 2:53pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962 "2016-12-31T14:53:35Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![boffking](https://avatars.discourse-cdn.com/v4/letter/b/858c86/32.png) [@boffking](https://boards.straightdope.com/u/boffking)\ **Post date:** [December 31, 2016, 2:53pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/1 "2016-12-31T14:53:35Z")
I have heard of great confusion being caused by UPS reusing old tracking numbers. A 16 character string that can include letters should provide a vast amount before having to use the same one twice. Of course, some of the digits could be checksums, or location/service based. How many possible tracking numbers are there really? ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 31, 2016, 2:58pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/2 "2016-12-31T14:58:41Z")
with UPS, only the last 8 characters are the actual package identifier. the first six characters after “1Z” are the shipper’s account code. > **[Tracking number](https://en.wikipedia.org/wiki/Tracking_number)** > > Tracking numbers are numbers assigned to packages when they are shipped. Tracking numbers are useful for knowing the location of time sensitive deliveries. It is a unique ID number or code assigned to a package or parcel. The tracking number is typically printed on the shipping label as a bar code that can be scanned by anyone with a bar code reader or smartphone. > In the United States, some of the carriers using tracking numbers include UPS, FedEx, and the United States Postal Service. Most post... > [@](#): > > A UPS tracking number, for domestic packages within the United States, will usually start with “1Z” followed by a 6 character shipper number (numbers and letters), a 2 digit service level indicator (e.g., 03 for GROUND, SEE UPS SERVICE CODES below), and finally 8 digits identifying the package, for a total of 18 characters ---
**Author:** ![Schnitte](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/schnitte/32/9033_2.png) [@Schnitte](https://boards.straightdope.com/u/Schnitte)\ **Post date:** [December 31, 2016, 3:04pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/3 "2016-12-31T15:04:30Z")
> [@jz78817](#): > > with UPS, only the last 8 characters are the actual package identifier. the first six characters after “1Z” are the shipper’s account code. > > [Tracking number - Wikipedia](https://en.wikipedia.org/wiki/Tracking_number) But would that mean that at least for each shipper account, there are 10[sup]8[/sup] = 100 million different numbers available? For each service level (as indicated on the Wiki article), that is, i.e. 100 million for next day, another 100 million for second day, another 100 million for regular ground delivery, etc.? ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [December 31, 2016, 3:50pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/4 "2016-12-31T15:50:22Z")
According to [their own website](https://www.ups.com/content/us/en/tracking/help/tracking/tnh.html), they can reuse numbers after 6 months, if need be. Unless I’m misinterpreting the information on that page, which I will concede is certainly a possibility. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [December 31, 2016, 3:54pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/5 "2016-12-31T15:54:29Z")
According to this [article](https://www.quora.com/How-many-Amazon-packages-are-delivered-per-day-and-what-percentages-of-the-total-are-delivered-domestically-in-the-US-and-internationally) citing 2015 stats, Amazon on _behalf of sellers_ shipped 2 billion packages in 2015 and over 200 million Amazon Prime packages that holiday season. Not all UPS, possibly not all domestic US, etc. But it seems Amazon can use up an 8 digit block in not too much time. Even giving Amazon a few extra shipping codes isn’t going to help in the long term. ---
**Author:** ![jz78817](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jz78817/32/1028_2.png) [@jz78817](https://boards.straightdope.com/u/jz78817)\ **Post date:** [December 31, 2016, 3:55pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/6 "2016-12-31T15:55:15Z")
> [@Schnitte](#): > > But would that mean that at least for each shipper account, there are 10[sup]8[/sup] = 100 million different numbers available? For each service level (as indicated on the Wiki article), that is, i.e. 100 million for next day, another 100 million for second day, another 100 million for regular ground delivery, etc.? Possibly (00000000-99999999) but that assumes none of them are “special” like check digits. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [December 31, 2016, 9:21pm UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/7 "2016-12-31T21:21:12Z")
> [@jz78817](#): > > Possibly (00000000-99999999) but that assumes none of them are “special” like check digits. I had assumed there was one but the Wikipedia article doesn’t mention it. OTOH, the [system](https://en.wikipedia.org/wiki/S10_(UPU_standard)) the USPS (and other postal services) uses does mention a check digit. ---
**Author:** ![SCAdian](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/scadian/32/3292_2.png) [@SCAdian](https://boards.straightdope.com/u/SCAdian)\ **Post date:** [January 1, 2017, 3:45am UTC](https://boards.straightdope.com/t/how-many-possible-ups-tracking-numbers/775962/8 "2017-01-01T03:45:44Z")
I do a lot of shipping for the company I work for, and for our account the numbers are assigned sequentially. Digits 11-17 started with 0000001 and are now somewhere up around 0016800. The final digit does appear to be a check sum.