Downloadable tool that helps you to determine the number of end users in a Site Collection or Farm.
The SharePointBoost End-User Viewer Tool is a free tool that displays the total number of end-users in a SharePoint Site Collection or Farm and gives the administratorthe ability to delete invalid/inactive user accounts.

Since the SharePointBoost licensing module is based on the number of end-users in a Site Collection or Farm, you will need to know how many users you have before you trial and purchase our products. This tool offers a quick way to check the total number of end-users you have WITHOUT installing it on your SharePoint servers. Simply download the SharePointBoost End-User Viewer Tool and run it by inputting the Site Collection URL, your username in the format domain\username and your password, and the total number of end-users and their account details will be displayed. You can then delete any expired or inactive user accounts, thereby reducing the need to purchase a license for a larger number of end-users.

Note:
Only Site Collection administrators can delete user accounts; Site Collection administrator accounts cannot be deleted;
"System Account" and "NT AUTHORITY\LOCAL SERVICE" will automatically be re-added to the Site Collection after being deleted.