Show percentage of disk full

Is there any way to, or maybe to add this feature, to show what percentage of the disk is full? FileRun can tell me the size of each file, but it does not show the total amount of space used on the disk. I'm using FileRun with a few connected hard drives (it points to 1 drive, but the other drives must be junction linked). I have no idea how much space is left on my hard drives and it's only a matter of time before the drive is full and I would have no idea when it's full.