Should the same user on two different devices count as 2 MTUs?

  • 1 February 2024
  • 1 reply

In Users & Sessions > User Look-up > Search Users, if I use advanced search to find a user by email, I find 2 or more (up to 16) Amplitude IDs mapped to the same email. It’s one person, and I assume this is due to use on separate devices (although 16 does seem odd, it’s just one person). I assume Amplitude is counting Amplitude IDs not unique emails, for MTUs. The result is almost 40% over-counting -- this is on a portal where everyone is logged in, so everyone has an email address.

Does this sound right? Is this a flaw in our implementation of Amplitude? Is there a way to still use Amplitude IDs but de-dupe tracked users so there is only one Amplitude ID per email? Or is that something I shouldn’t want for some reason? 

1 reply

Userlevel 4
Badge +8

Hi @Geoff Canyon here is Amplitude’s latest documentation on how MTUs are calculated across your org:


Would you be able to share 3 sample links to the 1 user’s different user lookup profiles that populate upon filtering on their email property? Are you able to check within each profile, is there a different User ID stamped on each profile despite having the same email?


Once a user is identified in your product, Amplitude is able to merge those devices into 1 catch-all user profile record. You mentioned this specific project is on a portal where everyone is logged in, so that simplifies ruling out anonymous users. However if your product is setting multiple User IDs for the same person, that’s where MTU tracking will be duplicated and 1 user’s actions will be split in multiple different user lookup profiles, based on each User ID