Bandwidth refers to how much data you can send through a network or modem connection. It is usually measured in bits per second, or "bps." You can think of bandwidth as a highway with cars traveling on it.
The highway is the network connection, and the cars are the data. The wider the highway, the more cars can travel on it at one time. Therefore more cars can get to their destinations faster.
The same principle applies to computer data -- the more bandwidth, the more information that can be transferred within a given amount of time.
The main difference between the basic and expensive plan of any hosting provider is the difference in the amount of bandwidth per month.
Most hosts will define the bandwidth amount in GB (Gigabytes; 1 GB = 1,000 MB). Below is an easy way to calculate the amount of bandwidth you will need for a month.
Total = visits a day * page views per visit * average page size * 30 (number of days a month)
Example for a site with 1000 visits a day, 4 page views per visit, and a page size of 45KB (kilobyte):
1000 * 4 * 45KB * 30 = 4,500,000KB = 4,500 MB = 4.5 GB
This website would require a plan with a minimum of 4.5 GB of bandwidth a month. However, to allow for growth, it would be wise to choose a plan with excess bandwidth in case there is an unusually large amount of visitors in a month.
Bits per second: How communication devices are rated. Kilo means 1,000, and mega means 1,000,000. Examples include 56k modem and 10Mbit Ethernet.
Bytes per second: The way data is measured on your hard drive and how file sharing and FTP programs measure transfer speeds. Kilo is 1,024, and mega is 1,048,576.
Read More: 3 most common questions about web hosting
Bandwidth is essentially a fixed amount of data that can travel over the Internet during a set period of time.
In other words, it is the amount of data that is transferred from your website to another computer. The more visitors you have, the more bandwidth you'll need to deliver your website to those computers.
Traveling from one computer to another is timed in bits per second (or bps). One bit is equivalent to one binary digit of information.
That binary digit is then used to form the text, graphics, and designs you see on your website.
Finally, don't forget that saving bandwidth is just as important as discovering how much bandwidth to purchase. So the next time you work on your website, remember these bandwidth saving tips:
1. A file compression utility can save space by compressing your graphic and image without distorting the image itself.
2. Instead of loading a large picture to your web host then using html coding to make it appear smaller when viewed, load the correct size image.
3. Write tight coding. Avoid duplicating "rules" and use script whenever possible.
4. Only offer .pdf files or downloads when they truly benefit your company.
5. Avoid offering RSS feeds that do not help promote your company or sell a product.
6. Drop forums that don't somehow contribute to the success of your business.
7. Use your robots.txt file to ban search engines from crawling web pages you do not want the public to view. You can also ban search engines from caching images.
8. Store your cascading style sheets in a file of their own.
9. Keep an eye out for unusual traffic as some people steal bandwidth by linking to your images instead of purchasing their own images.
10. Now go out and purchase web space for your domain and get off those free web servers!