Bandwidth in its simplest terms refers to the amount of data that flows across a network wire in a given time period. For most web hosting providers, that time period is measured in a month. Web hosting providers are charged a certain amount per month or per year for an allocated amount of bandwidth from backbone providers and wholesale data centers. That cost is then passed on to the consumer in the form of web hosting plans.
How much bandwidth will my website use?
With so much variation among web hosting companies, it can sometimes be difficult to know how much bandwidth your website will need. So, how much is a gigabyte of bandwidth anyway? Let's put it in perspective. If an average web page, images and all is 50 kilobytes in size, your website could be viewed 20,000 times! For the average hobby website, that is more than enough. Let's further put that 20,000 in perspective. If each visitor to your website viewed an average of 4 pages per month, it would still represent over 5,000 unique visitors to your website every month.
Beware of bandwidth usage when offering file downloads
While offering simple web pages doesn't use up much bandwidth, the same can't be said about downloading files. If you plan on allowing people to download music files, pdf files, flash files, or video files, you can eat up bandwidth in a hurry even with a relatively small number of people visiting your website. If your website offers an adobe .pdf file that is 1 megabyte in size, with one gigabyte of bandwidth, you will only be able to serve up one thousand downloads. This does not including the html needed to get people to download the pdf in the first place.
Video files eat up even more space. A one megabyte video file represents only seconds of video. For a half hour presentation, your video file could easily be over two hundred megabytes in size! At that size, one gigabyte would only allow you to offer five downloads to your visitors. What you plan to do with your website most definitely will affect how much monthly bandwidth you anticipate needing.
Overselling bandwidth is common in the web hosting industry
Because more people use only a fraction of their allotted bandwidth per month, most web hosting providers price their plans knowing that most people will only use a fraction of the resources available to them. In fact, with most companies, if you did use the maximum bandwidth available to you each month, you would most likely be shut down. If you go with a shared hosting account, your website can be hosted with hundreds or thousands of other websites. If your website starts to use a significant portion of the server's resources, you may find them pulling the plug on your website. If you know your website is going to need significant resources, you should probably consider getting yourself a dedicated server.
Knowing what you plan to do will allow you to know how much you need
By knowing what you plan to do with your hosting account, you can have a pretty good idea of how much bandwidth you're going to need. If you anticipate that you will be needing to serve lots of multimedia including video, music and large amounts of flash powered pages, you may need to consider going with a dedicated server. If your website is just starting out and you have little money and no real idea of how much bandwidth you're going to need, pick a company that gives you more than you think you'll need at a reasonable price. Make sure you also find out how much they will charge you for any bandwidth you use above and beyond what comes in your hosting package. If it is one dollar per megabyte and you've already exceeded a twenty gigabyte bandwidth limit, changes are, you'll get one hefty bill at the end of the month. When shopping around and looking at bandwidth, keep the overage cost in mind as well and you'll do fine.