There are some web hosting services that seem to offer a large amount of bandwidth. Before you jump at their offer, first evaluate just how much bandwidth you will actually need. Furthermore, does the service offer unlimited domains? If so, ask yourself how many sites you will set up on one account.
Most websites will have a mixture of both text and images. Your site may even offer downloadable files. Furthermore, the traffic of a website can vary significantly. In most cases, the average website will receive between 50 and 500 visits per day. In this case 3 to 5 GB of transfer per month should be more than enough for you. However, if you are looking to have a website that receives more than 500 visitors per day, then perhaps a hosting plan with more than 50 GB of data transfer per month should be considered. If you are hosting more than one domain on your account, figure out how many visitors you expect for each website and that is how you will calculate how much bandwidth per month you will need.
If you are a beginning webmaster you may be wondering how you will know how much data transfer is right for you. Really, that will only require that you do some simple calculations. If your website contains four pages that are each 50,000 bytes then you can multiply the number of pages times the number of bytes- which is 200,000 bytes. If the normal webpage viewer will look at half of the pages on your site then divide that number by two. This will tell you that each visitor would use 100,000 bytes per visit. There are 1 billion bytes in each gigabyte so multiply the number of gigabytes in your hosting plan per month by 1,000,000,000 bytes.
If your hosting provider provides you with 4 gigabytes of bandwidth per month that would be 4,000,000,000 bytes. Now divide that by the amount of typical bytes each user would use. In this situation each user is using 100,000 bytes per visit. With these numbers you can assume that your websites will be able to receive almost 40,000 visitors each month before exceeding bandwidth.
Of course, if you have a website that includes more images or content then your visitors may use larger amounts of bytes per visit. Just use the formula given above to figure out how much bandwidth is right for you. Finally, shop around before choosing your web host.