How Do You Calculate The File Size Of Your Web Site? 

1. First you need to understand how file size is measured. The smallest unit on a computer is a bit. One bit is one electronic on or off pulse. 8 bits strung together make one byte. One byte of
   information can put a letter, such as "B" on your screen.  If you put 1024 bytes together and then you have one unit of information called a kilobyte. Put 1024 kilobytes together and
   you have a megabyte. (Most floppy disks hold around 1.4 megabytes of information). Most of your graphics and web pages are measured in megabytes. 
2. To determine your total site file size, right click on the root folder where your web site is housed - this will not only give you the total site size but also how many files and folders are contained in your site. 
3. If you use an editor, such as FrontPage, go to the reports view, click on the site summary and you will get a reading of the total site file size. In Dreamweaver, just use the method in No 2.
   
   Prepare To Expand Your Hosting Plan You may want to add pages, graphics, features eg scripts, databases etc, to your site in the future. Begin with a small hosting plan at first (even 5mb is enough to start out with), and then expand it as you add new features.
   
   Check with your web host, if you can easily upgrade your hosting plan as you grow your site. You don't want to go through the hassle of changing hosts every few months.
   
   Once you have determined your total site file size, check what hosting plan you have purchased and how much disc space has been allocated for your site.

If you are only using 3mb of disc space but are paying for 100mb, then you may want to switch hosting plans and save yourself a ton of money each year.