Method to determine storage space may vary depending on operating System. This tutorial will cover the method for Mac OS Snow Leopard and Mac OS Mavricks. Specifically 10.6.8 for Snow Leopard and 10.9.4 for Mavericks.
take me to Mac OS Mavricks method
Step 1 in Mac OS Snow Leopard: open finder.
Step 2 in Mac OS Snow Leopard: select MacIntosh HD and open Get Info by using "command I" or right click and select "Get Info" from popup menu.
Step 3 in Mac OS Snow Leopard: view drive Capacity and Available storage space in the "Get Info" pane.
Alternately, you can view available storage space at the bottom of any finder pane.
Step 1 in Mac OS Mavericks: click the apple found in the top left portion of your screen to open menu. And, step 2 click "About This Mac".
Step 3 in Mac OS Mavericks: click "More Info. . ."
step 4 in Mac OS Mavericks: choose option A and click "Storage". Or, choose option B and click "System Report"
In Mac OS Mavericks option A: view graphical results for storage space availability.
In Mac OS Mavericks option B: view Available and Capacity for storage space.