When you sign up for a web hosting account, you'll be given a certain amount of disk space. This space holds all the files and data that make up your web site - HTML files, images, video, scripts, audio, etc. Generally, the higher the cost of the hosting plan, the more disk space you will be allotted.

A simple site with just a few basic pages of text doesn't need much space - likely less than 1MB. As your content increases and you add things like downloads, images, and multimedia content, you'll need more space.

Email messages also take up space. Incoming messages are stored on your server until you download them (and in some cases even after). If you get a large amount of spam, this can eat up a significant amount of your disk space. It's a good idea to go through your email on a fairly regular basis and clear out anything you don't need to keep.

What happens if you exceed your disk space? This depends on your web host's particular policies but in most cases you are charged for the extra space. These charges can be excessive so you should always be aware of how much space you're using. If you're getting close to your limit, it will be cheaper to upgrade before you go over, rather than pay a penalty.

To find out how much space you're using, you usually just need to log into your hosting control panel. These control panels let you perform all kinds of tasks on your web site and they usually have a section where you can see how much space you're using and how much is still available.

If your web host doesn't offer a control panel, you can get a pretty good idea how much space you're using by downloading your entire site to your computer and checking how much space it uses there.

To give you a rough idea, the average web page with 3 small images and 2 screens worth of text takes about 20Kb. With these types of pages, a hosting plan that gives you 10MB can hold about 500 pages.

Most websites are less than 50 pages, so a 10MB hosting plan is plenty to get started.

If you're adding multimedia content to your site, your needs will be quite a bit higher. For example, an average 3 minute MP3 file will use about 2.5 to 3MB.

A good rule of thumb if you're hosting multimedia content is to determine the total size of all the files you will be uploading initially and double that amount. This will give you plenty of room for growth.