This answer is AI-generated.

A few things in Box's own help articles usually explain this:

1. Check that the files really left your folders
Box says items in Trash don't count towards your storage, so moving them to Trash should already free the space. If the number hasn't moved, open Trash (left sidebar > More > Trash) and confirm the large files are actually there, and not still sitting in another folder.

2. Older versions count too
Box's storage figure includes every file and its versions. If you deleted a few big files but other large files have many saved versions, those versions are still using space.

3. Folders you collaborate in count for the owner, not you
If the big files were in a folder someone else owns, they were never part of your storage, so deleting them won't change your total. Only content in folders you own counts towards yours.

4. Give the total time to update
Box says the storage number is a display total that can lag behind: usually within an hour, up to 24 hours for larger changes, and in rare cases a few days to a week. Your files aren't affected by this, only the number shown.

If it still shows full after a day or so and the points above don't explain it, submit a request to Box Support and say the storage usage looks incorrect. They can look at the totals on your account.