Your Trash folder counts against your used space, old versions of files that have been uploaded are included with this as well.

Thanks Paul, this is a common problem on the support with no user fix.

Account empty, trash empty.

Hi there, 

Welcome to Box Community and glad to help! 

We've corrected your storage count. To verify this, log in to box.com> Account Settings> Used Storage. 

Let us know in this forum if you happen to experience this issue again. https://support.box.com/hc/en-us/articles/360043695334-Storage-Usage-Or-File-Count-In-My-Account-Is-Incorrect

Thanks for posting!