It can be useful to know how big a folder on your computer is (ie how much data is stored in there), or to learn how large an individual file is.

Go to Windows Explorer and right-click on the file, folder or drive that you’re investigating. From the menu that appears, go to Properties. This will show you the total file/drive size. 

A folder will show you the size in writing, a drive will show you a pie chart to make it easier to see. Used space is shown in Blue in the pie chart and the free space is shown in dark Pink.