Luckily, there are several software utilities that can help you figure out what is taking up all of your hard drive space. We recommend a free utility called WhatSize for your Macintosh computer. (If you have a Windows PC instead, read this)

Download WhatSize here

After you copy WhatSize to your Applications folder, run it, and it start to measure how much disk space each folder on your Mac is taking up.  It displays a finder-like window, fully navigable, that will show you a list of all the folders on your hard drive and how much disk space they are taking up. You can even look at each subfolder, and it will tell you exactly what each folder is doing to add to your hard drive crunch.

WhatSize is free and easy to use - I use it myself every so often to make sure that I'm not keeping unnecessary disk-hogs on my MacBook!