Microsoft's latest operating system, Windows 10, is now being used on 500 million devices every month, the company says.



CEO Satya Nadella announced the milestone in his keynote address Wednesday morning at Microsoft's Build conference for developers in Seattle.

At the 2015 Build conference in April of that year, a few months before Windows 10 launched, Windows chief Terry Myerson predicted the operating system would be installed on 1 billion devices within three years. But last year Microsoft acknowledged that it wouldn't hit that goal.

The milestone counts devices, not individual users, because some users may have multiple PCs running Windows 10, which the company cannot easily track.

This report is more conservative than some of Microsoft's past Windows usage milestones because it counts devices on which Windows 10 is actually installed and used. In the past, Microsoft has sometimes counted licenses that have been sold but not actually rolled out by big organizations.

Nadella also gave some other usage stats for Microsoft products:

Cortana, Microsoft's digital assistant, which is built into Windows 10, is used by 140 million people every month.

Office 365 has more than 100 million people using it per month in businesses or other organizations ("monthly commercial active users:).

Microsoft's cloud is used by more than 90 percent of the Fortune 500.

Nadella and other execs are slated to talk at the Build keynote Wednesday morning. You can follow the live stream here.