Missing 15 GB of HD space?

[ProMod]

I'm a longtime Mac user, but this one has me feeling like a newbie.

I'm calculating my hard drive space used before I switch over to an SSD. I added up everything and came up with 215 GB being used, whereas the system reports 230 GB are being used. What's going on here? Here's the breakdown:

500 GB drive

Library: 8.63 GB
System: 4.39 GB
Applications: 13.25 GB
Users: 189.20 GB

Total: 215.47 GB

System reports 230.31 GB utilized.

What else is there? What am I missing here? I know there is certain overhead space of a drive that can't be used, but 15 GB?

Thanks!
MC

 

[GGJstudios]

Use DiskInventory X (pre-Lion), OmniDiskSweeper, JDisk Report or GrandPerspective to see how space is being used on your drive.

 

[ProMod]

Thanks for the tip. I just ran OmniDisksweeper, and it's showing an 8 GB virtual memory file, understandable since I have 8 GB of RAM. Forgot about that.

What's weird is that it shows my Users folder as being 176 GB, whereas OS X shows it as being 189 GB. Any idea what could be accounting for that difference?

 

[heisenberg123]

Thanks for the tip. I just ran OmniDisksweeper, and it's showing an 8 GB virtual memory file, understandable since I have 8 GB of RAM. Forgot about that.

What's weird is that it shows my Users folder as being 176 GB, whereas OS X shows it as being 189 GB. Any idea what could be accounting for that difference?

Local time machine snapshots?

 

[ProMod]

Local time machine snapshots?

I think that's a new Lion-only feature.