It took about twice as long as originally promised, but Windows 10 is finally in active use by over one billion users on over one billion devices. The vast majority of which, of course, are traditional PCs.

“We’re delighted to announce that over one billion people have chosen Windows 10 across 200 countries resulting in more than one billion active Windows 10 devices,” Microsoft corporate vice president Yusuf Mehdi writes in the announcement. “We couldn’t be more grateful to our customers, partners, and employees for helping us get here.”

One billion is a big number—as Microsoft notes, that’s one out of every seven people on the planet—but the bigger news here, perhaps, is that the company is for the first time literally describing users and not just devices/PCs. In all of its previous usage milestone announcements, Microsoft only talked up how many active devices on which Windows 10 was installed. (The most recent figures were 600 million in November 2017, 800 million in March 2019, and then 900 million in late September 2019.)

The one billion figure is also important because previous Windows chief Terry Myerson had promised in January 2015 that Windows 10 would be in active use on that many devices “within two or three years.” But in July 2016, one year after the initial release of Windows 10, Microsoft admitted through an overly-friendly blogger that it would not reach one billion active devices in the promised time frame. I had previously predicted that it would never meet that goal. And when Myerson was later found to have been inflating the Windows 10 usage numbers by counting virtual machine (VM) installs, he was asked to step down in March 2018.

Microsoft also claims in its announcement post that there are now 17.5 million Windows Insiders worldwide, and that their “feedback shapes the development process” of Windows 10. While I’ve been told that only about one million Insiders are actually active in the program, the more pertinent number is that 100 percent of the Fortune 500 is now using Windows 10. This speaks to Windows 10’s real most important constituency, and to the “digital transformation” Microsoft is trying to drive in the enterprise.

“Reaching a billion people with Windows 10 is just the beginning,” Mehdi claims. “We will invest in Windows not only within Windows 10 for PCs but also across many other Windows editions, serving diverse customer needs including Windows IoT, Windows 10 Teams edition for Surface Hub, Windows Server, Windows Mixed Reality on HoloLens, Windows 10 in S mode, Windows 10X and more.”

Windows 10 is in good company: By comparison, Apple said in early 2019 that it had over 900 million iPhone users and 1.4 billion users overall, while Google said last May that there were over 2.5 billion Android users.