The list of active users / used licenses can be counted by using the Users tab on DESelect Admin Panel.
To access Users on Admin Panel:
- Navigate to the Admin Panel. Refer to this link on how you can access it.
- On the Admin Panel sidebar, under Administration, choose Users.
On the Users page, you will have the list of all the active users indicated by the Active flag.
In case a user is active in multiple business units, it still counts as one user.
Note that removing access for a user in Marketing Cloud to the DESelect Installed Package does not automatically change the active flag on a user.
Find out here how you can transfer user licenses.