The current data transfer market

The available data transfer in web hosting plans is constantly increasing and these days it's not uncommon to find 100 gigabytes monthly data transfer even in a sub $10 hosting account.

Data transfer units

The relevant units for this article are kb(s) (kilobyte(s)), mb(s) (megabyte(s)) and gb(s) (gigabyte(s)). One megabyte is 1024 kilobytes and one gigabyte is 1024 megabytes. But to keep things a little simpler, we will round these numbers down to 1000.

Example scenarios

For this article, we will look at two examples. One light and real website (Goodwebhosting.info) and one heavier imaginary website. Let's say it's a magazine style website with longer articles and a few pictures for each article.

A light website

Goodwebhosting.info is a light website. Mainly text, compact html code, css code in separate documents and just a little graphics. According to Awstats the average data transfer per page view is below 6 kbs, but currently, feed spiders are not filtered out and these are hitting the rss feeds quite often. So the average data transfer per viewed page is a bit higher.

Most pages are a little above 10 kbs, the graphical elements weigh in at a total of 4 kbs and the screen stylesheet is 4 kbs. The graphical elements (logo and sitemeter icon) and the stylesheet are stored in the browser cache so these are only transferred on the first page view. So the first page view from a visitor uses 18 kbs data transfer and the following page views takes another 10 kbs. For the sake of simplicity, we can say that each page view takes 15 kbs.

So a light website will use 15 kbs for each human page view. Now it's hard to estimate the number of visitors to a website but if your site is moderately popular with 10 000 monthly page views that results in 150 000 kbs data tranfer. With 100 000 monthly page views you will use 1 500 000 kbs. In the more relevant gb unit those numbers are 0.15 and 1.5. Add some heavy spider traffic and a light, popular website needs 2 gb monthly data transfer.

Heavier website

The imaginary website is a little heavier. An average page is quite long, 20 kb page weight without images, and 3-4 article pictures of 15-25 kb so we can estimate around 100 kilobytes per page view.

The data transfer used with the page view numbers above are 1 gb and 10 gigabytes not including bot/spider traffic. Bots and spiders are harder to estimate but they depend mainly on the amount of content/updates and will normally not increase with the amount of human page views.

Results

We have now established that a light and popular website doesn't need more than 2-3 gigabytes of monthly data transfer. Most web hosting providers these days, even those who are not participating in the gigabyte race offers 5-10 gigabytes in their starter accounts.

And even a website with heavier content can start in that range. You might need more in the future but it takes time to develop traffic and you can upgrade as needed when the time comes.

Things to watch out for

While the above estimates are partly based on real numbers, your reality can be different so keep your eyes open.

Your actual data transfer usage

Check your statistics. Your control panel should have charts/tables that show your data transfer usage. A log analyzer like Awstats can also give valuable data about how the data tranfer is distributed between pages/file types/user agents etc.. NB! Javascript trackers like Sitemeter and Google Analytics can not report data transfer.

Feed warning!

Even if xml feeds (rss/atom) are very small in size, they are hit often and can result in significant data transfer.

TOS limitations

Web hosts might have clauses in their terms of service that limits your data transfer usage in addition to the normal data transfer quota. So make sure that you read the terms of service even if it is boring.

One example from a budget host is the following:

Binary files such as images, video and sound (i.e MP3, WAV, RA, GIF, JPG but not limited to those file extensions) may only account for a maximum of 50% of Customer's total bandwidth usage before customer must upgrade to a higher performance solution.