Bandwidth is used to measure the volume of data transmitted on an Internet connection. You need to know the amount of bandwidth you need when choosing webhost plans. Be wary when a company claims that they can provide unlimited bandwidth or unlimited monthly transfer. Anyone the claims to offer “unlimited bandwidth” is simply using screwed marketing tactics- there is simply no such thing.
Bandwidth
To date, there is no broadband company that offers Internet connection and offers unlimited megabytes/sec.  That said, how can a webhost company, which normally does not even have its own access lines, say that they can offer their customers “unlimited bandwidth”?
Most often than not, sites that uses high bandwidth on these “unlimited” plans will eventually be disconnected and no refund will be given back. Usually, the web hosting company will claim that your website site did not follow its Acceptable Use Policy or Terms of Service.
Each time you visit a site promoting “unlimited bandwidth” as one of the features of their hosting plans, be sure to visit the Acceptable Use Policy or Terms of Service. Always read this part and you will sure find something that will talk about their “unlimited” disclaimer and how they can easily suspend sites.
The first time you are looking for web hosting services, you must make your best guess and check your usage carefully in your first few months. Here are some of the things to ponder:
  1. How many possible visitors will access your website?
  2. How many pages are available for access?
  3. How big are your graphics and HTML files?

Large audio or video files, software downloads and files require more bandwidth. Flash sites use a large amount of bandwidth too. Virtual Reality (VR) and full-body and 3D audio / visual presentations require more bandwidth for everyone.

Do not fall into the trap of unlimited bandwidth that some companies offer you. Be wise and read through all features and limitations of the web hosting plan you will choose. Also read How is Bandwidth stolen? to reduce your Bandwidth usage.