What Percentage of Users have the .net Framework Installed (and what versions)

When I read forums used by software developers I often see people saying they can’t use .net (or some feature of .net) in their product because .net is a huge download, from my experience installing .net from the setup program of your own software is really not a big deal but I wanted to see the real numbers for .net installations.

The numbers are based on visits to this site from mid December (when I installed a new analytics software that let me get this number) until mid April (when I wrote this blog post), because I regularly blog about WPF visitors of my blog tend to have the latest version of .net installed, to remove this bias I only included people who downloaded the trial version of yaTimer (unfortunately programmers reading about WPF are highly unlikely to download time tracking software).

I used the browser user agent string to determine the .net version, Internet explorer always report all installed versions of .net (I disregarded all but the latest), FireFox reports only the latest version and only if it has the ClickOnce plug-in installed, other browsers (Google Chrome, Opera, Safari …) don’t report the .net version at all.

39% of visitors are using browsers that don’t report the .net version – I don’t have any information about those so I’m going to disregard them, I’m also going to throw away results from FireFox because I think they produce bias because the ClickOnce plug-in is included with .net 3.5 SP1.

Here are the results in all their glory:

	Version	Percentage
	none	17%
	1.0	0%
	1.1	3%
	2.0	24%
	3.0	30%
	3.5	5%
	3.5SP1	21%

Or, to put it another way:

17% of visitors don’t have .net at all

80% of visitors are able to run .net 2.0 software without any lengthy download or installation.

56% of visitors have .net 3.0 or later and can use WPF, WCF and WF.

And this information is from mid April 2009, Microsoft is rolling out .net 3.5SP1 via windows updates for everyone with .net 2.0 or later, so I expect the numbers to get even better.