We’ve seen official statements that Windows 10 was installed on 75 million machines in its first month and unofficial news that it’s on 81 million a week later. That 81 number prompted us to take a look at how Windows 10 compares to its predecessor according to AdDuplex data.

As you can see, in the comparison of the latest 2 versions of Windows the previous one is still in the lead but it seems that it’s not for long. Windows 10 represents a 39% share already. Most of these machines were upgraded from 8.1, but some may have upgraded from Windows 7 or came with Windows 10 pre-installed.

There’s one type of Windows 8.1 devices that has no option to upgrade to 10 – Windows RT tablets. Most of these are represented by Surface RT and Surface 2, and since running Store apps was the only way for them, they represent a significant portion of devices in our data. So, it would make sense to discard them to see a better upgrade picture.

This way Windows 10 gets even closer to parity with 8.1. Any bets on when it’s going to catch up?

Data source

These stats are based on data from 173 Windows 8.1 apps running a recent version of AdDuplex ad SDK collected on September 8th, 2015. All of these apps are capable of running on both Windows 8.1 and Windows 10 but don’t support Windows 8.0.