I have a backup which in the file explorer is about 160 GB.
If I run
select sum ((size * 8) / 1024) From sys.database_files where type = 0
I get a result of 169493, good.
When I try to restore this database to another server (the former database administrator created a job that automatically restores the database every morning from the last backup, and then runs DBCC CHECKDB). If I try to VERIFYONLY RESTORE, it turns out that I need 288 GB for this to work. Why? The backup is not compressed.