When looking for a web hosting plan, you need to consider how much bandwidth you might need to have. Bandwidth, as related to how web hosts sells their plans, refers to the total amount of data that can be transferred to and from your website each month, usually advertised and sold by GB (gigabytes). This transferring data includes html files, graphics, audio/video, e-mail messages, and any other files that are a part of your Web site.

Tip: When a person visits your website, they are “downloading” the page they are looking at, so it counts towards your bandwidth usage.

First, a little math. One KB is 1,000 bytes, one MB is 1,000 KB, and One GB is equal to 1,000 MB. For practical purposes, one GB is equal to 1,000,000,000 bytes. (Always round off  KB or MB to the next highest number for your calculations.) Yes, I know that one KB is actually 1,024 bytes, but most web hosts use the 1,000 bytes.

We are going to use a practical example to show how bandwidth works. You are going to water your lawn everyday. The total amount of water you use in a month is what you will pay for. Bandwidth is similar to the water. The total amount of data you processed is the same as total bandwidth you used during the month.

Example: A MP3 song is on the average 4Mb in size. Let’s say you download 5 MP3s per day from a web page that is  2MB in size. Then, for the entire month, the bandwidth usage for only the MP3 downloads is:

6 MB (MP3 + page size) times 5 (downloads per day) times 31 (days) = 930MB. This is only an example if you are uploading or downloading files from your website.

So, the general formula for those websites that are not involved in downloading or uploading files for use by their customers is:

Average Daily Visitors x Average Page Views x Average Page Size x Number of Days in Month x Fudge Factor = Bandwidth Required

If you are just putting up a new website, you will probably have to do two things: First, best-guess at the missing figures, and two, monitor your bandwidth.

Here are some definitions for you:

Average Daily Visitors. Total number of visitors you expect for the entire month, divided by number of average days in month (30). For example, you have or expect 300 visitors per month to your website. So you would divide 300 by 30 to get a daily average daily of 10.

Average Page Views. The total number of page views in a month divided by the total number of visits in the same month. For example, you know the total page views in a month is 6,000 with a total of 300 visitors. So the average Page views, [3,000 total pages / 300 visitors], would be 10 average page views.

If you are starting off fresh without any real numbers, you could simply use the total number of web pages you have with the assumption that every visitor is going to look at every page on your website, (wouldn’t that be great?). So we will assume for this example that you have 10 pages on your website.

Average Page Size. This is the average size of all of your web pages AND files in your website measured in KB. If you have your website completed, add all of the totals of all pages and then divide by the number of pages you have. For instance, using our 10 pages you have in your website, you add each file size up, for a total of 190 KB. The average would be 190 / 10 = 19 KB.

Tip: When adding these up, always round up to the next KB, i.e., the file is 4.2 KB so use 5KB)

Number of days per month. While the average used is usually 30, we will use 31 to be on the safe side, as well as account for those months when there are 31 days.

Fudge Factor. This is where you can be as flexible as you want. We would recommend that you use either 1.5 or 2 for standard websites or small business websites. If you are going to have a lot of photos, product pages, etc., you may want to even use 3.

So, for the formula with our figures, we have:

10 Average Daily Visitors x 10 Average Page Views x 19KB Average Page Size x 31 Number of Days in Month x 1.5 Fudge Factor = 883,500KB or 1 GB Bandwidth Required (rounded up)

And there you have it. Obviously, these are only example figures but it should give you an idea on how to determine what you need.

Some final Notes:

1. When you check with the web host you want to use, see if they rate limit your server. This means they restrict the maximum amount of bandwidth that may be used at any point in time. For small business that have shopping carts, this could cause some problems.

2. Always check your Bandwidth Usage History through your web host. This will give you plenty of warning in advance as to whether or not your bandwidth needs to be increased. Better to upgrade to the next higher plan than get surprised with a bill at the end of month for what could be a much higher expense.

3. When adding up totals for the Average Page Size, make sure you include the size of all files and files within all folders in the directory where your website is stored. Web hosts often count those as well because you usually can not view a web page without use of some of the application files included at the server level, i.e., cgi-bin.

If you have questions, always ask your web host and/or your webmaster. Both should be more than willing to help you.