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Load size analysis of the top 100 blogs

This report presents an analysis of 100 top blogs, picked from the Technorati top 100 list. For each of these blogs, the front page (homepage) has been analyzed to see how large its download size is and what contributes the most to this size.

We have chosen to not present the blogs individually in this report, but have instead focused on them as a group to get more general data.

Total blog front page size

The size difference between the different blog front pages was very large. One front page was close to 6 MB in size, though it is an extreme case and should not be considered representative. Most blog front pages, 93%, were below 2 MB in size.

  • The average total size of the front page was 934 KB.
  • 35% had a front page larger than 1 MB.
  • 26% had a front page smaller than 500 KB.
  • 39% (the largest segment) had a front page between 500 KB and 1 MB.

Images and scripts the largest contributors to size

When averaging all the 100 blogs included in the survey, it was clear that the single largest contributor to the size of the front page was images, which in itself should not come as a surprise considering that today’s blogs often are very visual and contain many images.

  • Images: 61.3%
  • Scripts: 17.2%
  • HTML: 15.3%
  • CSS: 5.9%

Number of images per page

On average, there were 63 images included on the front page, though the number varied greatly. Some had less than 10 images, while others had more than 100. You can see the distribution in the diagram below.

In addition to images in the posts themselves, images are also common in the design of the layout of the blog, which can explain the large number found in some blogs. Both images included in the HTML and the CSS are included in this count.

Number of scripts per page

On average, there were 9 script files included on the front page, and here too the number was very varied between the different blogs. The page with the most scripts had as many as 35 script files included.

Scripts are often included from external sources, for example visitor statistics scripts such as Google Analytics and Sitemeter. Other examples are WordPress plugins, which often add their own Javascript files to the blog.

Blog readers without broadband left stranded

As this survey has shown, three out of four blogs have front pages larger than 500 KB, and more than one third have a front page larger than 1 MB.

With an ideal, perfect connection, this is how long it takes to download 1 MB (1048576 byte) of data:

  • 56 kbit/s modem: 2 minutes and 30 seconds
  • 256 kbit/s (minimum limit for broadband): 33 seconds
  • 384 kbit/s (3G “low speed”): 22 seconds
  • 1 mbit/s (low-end broadband): 8.4 seconds
  • 10 mbit/s: 0.84 seconds

Note, however, that this assumes that the bandwidth is utilized to 100%, which normally won’t happen. The above numbers just show you the theoretical upper limit.

In short, blog readers with slower connections will have problems loading the front page of many of today’s blogs, at least with images enabled.

Size and speed optimization of blogs

Since images constitute almost two thirds of the size of the entire page on average, it would seem logical to start the optimization there. This can be done in two ways (which are not mutually exclusive):

  • Optimize the size of the images. Depending on its content, an image size can be optimized by choosing an appropriate format, compression level, color depth, and other relevant settings.
  • Use fewer images (many blogs have a large number of small image elements). This will also have the positive side effect of fewer requests being made to the web server which is also beneficial for performance. One way of having fewer images is the use of so-called sprites, where several images are stored in one.

Since scripts came in second, size wise, here are a few tips that apply to reducing the impact of scripts on the load time:

  • It can be a good idea to see if it is possible to reduce the number of scripts used on a blog. Are all of them really necessary? Are there for example scripts present from WordPress plugins that you are not using anymore?
  • Since reducing the number of requests to the web server is a good way to enhance performance, it is often a good idea to merge all your scripts (or at least most of them) into one file, making it one single download.
  • Another factor to consider is that by including external scripts, a blog’s load time can be affected by loading issues with that external script (which is outside the blog owner’s control).

These are just a few advice regarding these specific areas. Website optimization is a huge subject and going into detail here would be outside the scope of this report.

Conclusion

There will of course be some size variations depending on the current content presented on the blogs, but the overall, average data is not bound to change much and is highly relevant, especially considering the large sample base.

Since many blogs try to attract a large number of readers, they may be doing themselves a disservice if they let their blog size get too big, which will result in a slow-loading blog. Browser-side caching will help things a bit for frequent readers, but any new or casual visitor will have to load the page in its entirety and some may give up before it is finished or at least get frustrated. (And no one wants frustrated readers.)

Even broadband users would benefit from smaller page sizes with fewer objects on them. This would speed up the responsiveness of the website for them as well. Ultimately it would also be beneficial for the blog owner since it would put less stress on his server(s) and demand less bandwidth.

We suspect that not all blog owners are really aware of how large their blog pages actually get, so we hope that this report will prove helpful in raising discussion around this subject. Some blogs are bound to be large, especially if the content relies heavily on images, but many others could most likely significantly reduce their download size (and download speed) with the few simple measures we mentioned above.


About the test

The data was collected with the Full Page Test in Pingdom Tools, which is a Web-based tool provided freely by Pingdom. It will load and analyze all elements of a web page and present the data in a way that can be examined and filtered with a simple interface.

The tests that provided the basis for this report were performed on October 30, 2008.



13 comments
Dhamphire
Dhamphire

Lately I have check my blogs stat through Google webmaster tool and I have discovered that my site loads slower that the usual loading time of a blog. I think I need to change theme because my current theme has an automatic image loader that really slows down the loading of my blog...

karen
karen

Sometimes you just cant win...like mentioned already, it HAS to look good, or people will not stick around, but if its too slow, they leave. Such the issue...I am trying some WP cache now, i think it helps but not really sure...Thanks Karen

Aurelius Tjin
Aurelius Tjin

Hey, that's a very great analysis mate! I want to do a similar analysis of my blog to figure some stuff out. Thanks for the heads up!

David Coveney
David Coveney

There's really no excuse for weighty sites - but it has to be said that a combination of designers who favour eye-candy over performance and functionality (yes, good looks are important, but only if you have a chance of seeing them - pity people on a poor link) and bloggers who have a bad case of plugin-itis have to stop and think. When we're building themes for WordPress or clients (I'm trying not to self-promote here, but bear with me) we make a point of testing on devices such as mobile phones, and with a throttled broadband connection. Ultimately it matters a lot of your users can't read your content. If you service a community of broadband connected geeks it's probably not so bad, but if you're trying to reach a broad audience then it's important to test test test. Yslow is your friend.

Kevin
Kevin

Great article. As has been said, great work on the graphs.

Pingdom
Pingdom

Thanks for the comments. _ck_: Yes, flash objects are not seen as images. Images are only png, gif and jpegs linked in the HTML and CSS code.

Shantanu Goel
Shantanu Goel

I recently analyzed the same thing about my site. I used a lot of images for my blog's navigation layouts etc and was running out of bandwidth every month. The main page total size stood at around 500 kb. I then switched to a newer layout that minimized the use of images and did its things with css and colors. Result: Main page now stands at < 80k. Bandwidth usage has also been cut into less than 1/4th.

redwall_hp
redwall_hp

Let's see... My blog, Webmaster-Source, currently clocks in at about 471 kilobytes for it's home page. There are 44 images, 57k worth of HTML and CSS, and 11 scripts. The tool I used to gather this data estimated 1.8 minutes to load the front page at 56k. Ouch. I'm still beating the pants of TechCrunch and company though. :D I'm also planning a redesign to try to declutter the blog while making it look better visually, and I'm hoping I'll be able to make load times a little quicker while I'm at it. Another major bottleneck, though, is the server. As I'm on shared hosting for the moment, pages aren't served as fast as they could be if I were using, say, a VPS. I'm planning on *eventually* moving to a VPS by Slicehost or Linode, which is faster by default and will allow some lower-level tweakage. I'm holding off on the move though because I want to save money while I can...

_ck_
_ck_

Nice analysis. Are you differentiating between images and flash objects? Over 500k in images in insane, even with broadband, because that is likely to defeat the browser cache after a day or two and then your site bandwidth use goes up and up and up.

Stephane Grenier
Stephane Grenier

I have to say I'm a bit surprised. But then again... To get a lot of traffic, the blog has to look good. But at the same time this means you only really cater to the higher bandwidth folks. But more than that, a common technique with blogging is to include at least one picture with each post. Assuming about 10 posts on your main page, that's at least 10 higher sized pictures. Then you have your theme's pictures. So I can see it quickly escalating to 1mb. I guess the bigger question is, where can you surf online today where you don't need broadband speeds? There's not many sites left that support modem speeds anymore.

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