Get Info command
2. Under the File menu, choose Get Info. (You can also press the Command key and the letter "i" key.)
3. The Get Info window will show the hard disk's capacity, space available, and space used.
Apple System Profiler
2. Under the Select menu, choose Volume Information.
3. The hard disk's capacity, space available, and additional information will be displayed.
Additionally the Apple System Profiler also shows you the following information: