If you have a lot of external disk drives attached to your PC via USB, then it can be easy to lose track of how much space you've got available on each.

One way round this is to use DiskSizes which shows at a glance, status information about your computer's drives and most importantly, how much space is left on them. The additional information it provides includes cluster sizes and the total size of each drive.

However, the utility goes beyond that also measuring a folder's disk use and displaying the number of folders, files and sum of the file sizes. This is very useful if you're trying to count how many folders are on a drive which is something that Windows doesn't normally tell you in Explorer. This is also useful if you are performing backups and are not sure when you did your last one - more folders than on your backup drive will indicate that you've definitely got remaining folders to backup.

It's a shame it doesn't display information in graphical form but as a simple hard disk space monitor, DiskSizes does a solid job.