For a webmaster, bandwidth is the measurement of data that is sent from the web host's server to the visitor's computer. If you have a lot of files that are downloaded by your visitors, or you have a lot of traffic, you are going to need more bandwidth. The fact is that many webmasters do not plan ahead and choose a hosting plan that includes enough bandwidth for website growth. If the bandwidth on the web hosting plan is ever exceeded, the site shuts down. This makes it even more important to ensure that the plan has enough bandwidth, because the last thing you want is to be so popular your site goes down for two weeks in the middle of the month. Well, the popularity is nice, yes, but the fact that your site is not up to cater to that popularity is not going to be.
So, how much bandwidth do you need? It is hard to tell until you start getting website analytics to help you see measures of your traffic and activity, and start getting statistics from your web host to see how much bandwidth is being used. It is important to remember though, web analytics programs are not 100% accurate, but they do provide a good indication of traffic and other measures.
To calculate how much bandwidth you think you may need, use this formula:
Total = visits a day * page views per visit * average page size * 30 (number of days a month)
In this example: If you get 1000 visits per day, and you have 5 page views per visit, with an average page size of 45KB, you would then multiply 1000 * 5 * 45 * 30 to get 6,750,000 KB per month.
Most hosting plans provide the bandwidth amount in terms of GB, so in this conversion, 1 GB = 1,000 MB 1 MB = 1,000 KB. To get the total GB in hosting, divide the KB by 1 million. We arrive at 6.75 GB, so to be safe, in this scenario, one should purchase a plan that allows for at least 7 GB worth of bandwidth to handle the high traffic volumes and prepare for traffic surges. The amount of bandwidth in a plan is usually one of the factors that controls the overall price of the plan, as well.
Granted, almost no site is going to need all of this right away, but failing to factor it in from the beginning is what causes many webmasters headache in the end. This is why it is very important to understand bandwidth in the beginning when choosing a web hosting plan.