How often is the default font size in the browser not 16px?

After writing a great big answer to the question Is it bad to wor开发者_JAVA百科k with pixels in CSS? in which I concluded that there's normally nothing wrong with it provided you understand the limitations, I started to wonder about how many people have the default font size set to something other than 16px.

I imagine that there would be some users who change it due to either poor eyesight or high pixel density monitors (like those with 1920*1080 screens on 15" laptops) (or maybe just because they like larger text). There also may be some devices (handheld devices?) that have the default font size set to something else, but this is purely conjecture on my part.

My question is: does anybody know any statistics on what percentage of users have the default browser font size set to something other than 16px?

This avoids answering your question, but IMHO such statistics shouldn't matter even if it were near zero percent.

Even if 16px were the de-facto standard, you should start from the position that this is something that the designer doesn't ultimately control, and it should be left up to the user to choose their font size. Your decision process should lead to designs that are flexible based on the user's needs.

I'm not sure if you've found much by way of google but this search bought up this page as hit 1: http://www.oreillynet.com/xml/blog/2006/03/more_statistics_on_user_clicks.html

Incidentally this question is on page one of the search too :)

Its from 2006, but the first bit has a little about the font size settings in IE.

I doubt there is any documented data for this specific thing.

One thing I can tell you is that in over 10 years of working around computers I've seen about 1 in 10 users having a above default DPI setting. eg. 120 that caused the font size to be bigger than 16px in their browser. It also caused layouts that weren't styled properly to break.

Late reply to the question; Defining your font size to a fixed size (px) or (pt) would mean that your site visitor can't increase the size of your Web page text. You might say "great", but this doesn't allow someone with visual disabilities to adjust browser settings to increase font size. If you're designing a website for the general public or for the government, this is a big "no-no".

To be on the safe side use relative measurements (em) or (%) that allow for font adjustment in a browser.