My database was 66 gigs, but after importing and moving the emails to the correct folders, it made my database 100 gigs.
If you have eM Client for Windows and believe that the database size should be smaller, then try closing eM Client and then running the following “rebuildall” command below in a command prompt window as per @Gary post from the following thread.
https://forum.emclient.com/t/optimize-database/89795/4
Gary’s post extract from the above thread.
Note: Before running, backup eM Client first via “Menu / Backup” incase you need to restore for any reason. You can see when the backup is complete in Show Operations via clicking the drop-down on the right of Refresh top left.