It happens like clockwork, around the first of each month. Sites that focus on technology churn out nearly identical articles, all based on a chart like this one, prepared by the good folks at Statcounter Global Stats.  

You’re going to see that chart a lot this week, embedded in posts that include detailed explanations of what the author thinks the underlying data points mean. Sometimes they even convince an industry analyst to share their thoughts. It’s stereotypical horserace coverage. This month, everyone will be attempting to explain why Windows 10 (the purple line at the top) is suddenly collapsing in popularity and why Windows 11 (the blue line in the middle) has regained its mojo.

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When I checked Google News early this morning, these stories were already up, and I’m sure more are on the way.

My favorite quote from this batch is from Forbes, which made this bold assertion: “The January stats are now out, and according to Statcounter, the Windows 11 upgrade trend has now un-reversed itself … some 40 million hold-outs have suddenly upgraded their PCs in the last 31 days.”

Inevitably, these posts try to answer the question, “Why did this happen?” But maybe a better question is, “Did this happen?” followed by “Are you sure?” and “Why doesn’t any of this data make sense?”

Because here’s the reality: Statcounter’s “market share” reports are a great excuse for tech bloggers to crank out a story each month, but they bear only the most casual relation to the real world, and most of those month-to-month spikes are simply statistical noise.

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Let me show you what I mean with another chart, which I created using data I downloaded from Statcounter’s site. For this one, I changed the parameters to include data from January 2022 through January 2025, covering only the United States. After plugging that data into Excel, I created a line chart like the ones they publish, but I made two changes. First, I added third-order polynomial trendlines for the Windows 10 and Windows 11 data points to show the general direction of those monthly figures over time. Then, I added a shadow on either side of that trendline to indicate a likely margin of error.

Well, that tells a very different story, doesn’t it?

At the sites that use Statcounter’s web analytics service, pageviews from PCs running Windows 10 are steadily declining, while pageviews from PCs running Windows 11 are steadily increasing. And those trends have been consistent over time, despite some fluctuations in the data.

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You’ll notice that description doesn’t mention “market share.” Statcounter’s data counts pageviews, not visits, or sessions, or individual devices.

And make no mistake about it, those monthly fluctuations really are just noise. Look at the teal-colored line for Windows 8.x versions from January 2024. Do you really think that 10 or 20 million people fired up their old Windows 8 devices on New Year’s Day, used them for a few weeks, and then put them all back in the closet? That’s unlikely.

None of those other monthly spikes mean anything either. Did millions of people uninstall Windows 11 in December 2024 and then change their mind a month later? Of course not. The data is just messy!

Now, let me be crystal clear here: I don’t blame the Statcounter folks for taking advantage of an irresistible opportunity to generate publicity. I do, however, want to have a serious talk with every journalist and analyst who relies on Statcounter’s charts without questioning the underlying data behind them, because those numbers can’t stand up to even the mildest questioning.

Who is Statcounter?

Statcounter is a web analytics company based in Ireland. It was founded in 1999, during the Web 1.0 era, with a simple business model of counting “hits” to websites using a tracking pixel that clients embedded on their pages. If you’re a website owner, adding Statcounter’s tracking technology to your site can give you valuable information about your visitors.

It was a good business for a long time, but over the years the company’s customer base has shrunk. In 2009, it boasted that 3 million customers were using its service. By 2022, its own pages acknowledged that the customer base had been cut in half, to 1.5 million websites.

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W3Techs, which tracks companies in this space, reported that 0.9% of all websites were using Statcounter’s services in 2019. By January 2024, that number had shrunk to 0.5%, and when I checked again in January 2025, the number was down again, to 0.4%.

None of that decline should be surprising. Google Analytics dominates this space today, and other big players, like Meta Pixel, WordPress Jetpack, and Adobe Analytics, have also stolen share from tiny firms like Statcounter.

Where do Statcounter’s numbers come from?

Statcounter’s customer base consists of a lot of small websites and a few medium-sized ones. The Statcounter Global Stats reports aggregate all the pageviews from those sites, with details about the visitors, including the hardware type, operating system, and browser, as collected by that tracking.

Statcounter’s data collection has declined dramatically in the last decade. A decade ago, the company’s FAQ page reported that it measured more than 17 billion pageviews in a typical month. By 2022 (the last numbers that Statcounter has provided on the current FAQ page), that number was down to 5 billion a month.

Statcounter represents a tiny sliver of actual traffic on the web, mostly from fairly esoteric websites that have chosen to embed the Statcounter tracking code on their websites, like  Futbin.com, Filmyzilla.com.fj, Ask.com, and Kernel.org. They can’t count traffic from the most popular sites on the web, like Google, Facebook, or Wikipedia.

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It’s like trying to do a survey of consumer behavior without including Costco, Walmart, Home Depot, Target, CVS, or any Kroger grocery store. By leaving out those giants, your sample becomes quirky and almost certainly not representative of the greater market.

More importantly, Statcounter measures only pageviews, not visits or sessions. If I go to a site that uses the Statcounter service and visit five pages on my Windows 11 PC, and you load 10 pages with your Windows 10 PC, the results in Statcounter’s “market share” report will show that Windows 10 is twice as popular as Windows 11. You see the problem here, I presume.

Of course, that assumes all those pageviews are even counted. On my Windows 11 PC, where I use Microsoft Edge with its tracking protection set to Strict, Statcounter’s tracking code is automatically blocked. Oops.

So, what’s the real story?

The data from Statcounter tells a perfectly valid story about how people use websites that belong to its customers. But it says nothing about the “market share” for Windows PCs.

It does show, in the most general terms, that traffic to those sites from Windows 10 PCs is declining slowly and that traffic from PCs running Windows 11 appears to be increasing slowly as well. Do those numbers map to the population of PCs worldwide? Probably not, although no one can say for sure.

Also: How to clear the cache on your Windows 11 PC (and why it makes such a big difference)

We do know that there are a very large number of PCs running Windows 10 that are not eligible to upgrade to Windows 11. That number will probably still be very large in October 2025, when support for Windows 10 ends. Someone with access to Microsoft’s telemetry servers could probably give you a pretty good estimate of how many devices are in each population, but they’re not talking.

The rest of us, unfortunately, are left to guess. And if you want to make a wager based on data from Statcounter, go right ahead. Just don’t put any serious money on that bet.