Ask Windows 11 the right way which version it’s running, and the answer still comes back as 10.0. Nearly five years after launch, Microsoft’s newest OS officially identifies with the same internal version number as Windows 10.
Microsoft officially identifies Windows 11 with the same 10.0 version number used by Windows 10, so this goes far beyond some upgrade-era leftover. Nearly five years after Windows 11 launched, the branding may say “11” everywhere you look, but deep in the plumbing, Windows is still answering to “10.0”.
Windows 11 really does call itself 10.0
Eleven upstairs, ten in the basement
You can see the split for yourself without installing any obscure diagnostic tool. Open Command Prompt, run systeminfo, and Windows will identify the product as Microsoft Windows 11 while listing the OS version as 10.0, followed by the build number. A Windows 11 25H2 machine, for instance, can report 10.0.26200 while still clearly calling itself Windows 11.
Microsoft’s own documentation lays out the same pattern. Its operating system version table lists Windows 7 as 6.1, Windows 8 as 6.2, Windows 8.1 as 6.3, and Windows 10 as 10.0. Windows 11 appears on the next line with the same version number, 10.0.
The branding number has never been a reliable mirror of the internal NT version, anyway. Windows 7 was not NT 7.0, and Windows 8.1 was not NT 8.1. The current mismatch only looks extra weird because Windows 10 happened to line up perfectly with NT 10.0, which made the numbering feel cleaner than it really was until Windows 11 came along.
Windows has been burned by version numbers before
Old software can be quite literal
Keeping 10.0 also fits neatly with a compatibility problem Microsoft has been wrestling with for decades. Windows has spent decades keeping old programs running on newer versions of the OS, and version checks are one of the places where that compatibility work can get messy. Code written around the releases that existed at the time can get confused the moment it sees a number the developer never expected.
Microsoft learned that lesson quite early. Windows veteran Raymond Chen explains that Windows 95’s GetVersion function reported version 3.95 instead of the expected 4.0 because so many applications were doing broken version checks. Some compared the major and minor numbers separately, so software looking for Windows 3.1 or newer could see the 4 in 4.0, then reject the 0 because it was lower than 1. At some point, accommodating the bad checks became easier than chasing down every application that made the wrong assumption.
That headache never really disappeared. Starting with Windows 8.1, Microsoft changed how APIs such as GetVersionEx behave, so the version an application sees can depend partly on which Windows releases its manifest says it supports. An app without the right declarations can still be handed Windows 8’s version number, 6.2, even while running on a much newer release.
Microsoft’s Version Helper functions follow the same careful approach. Rather than encouraging developers to look for a specific version number, Microsoft provides checks such as IsWindows10OrGreater and recommends greater-than-or-equal-to comparisons that are less likely to break as Windows evolves.
Microsoft has never published a definitive explanation stating that compatibility was the sole reason Windows 11 stayed on NT 10.0, but the choice makes a lot of sense in that context. Windows carries decades of applications and drivers built around assumptions Microsoft can’t retroactively rewrite, and changing an engineering-facing number to match the marketing name would give old software one more opportunity to trip over itself.
The build number has silently taken over
Windows 11 has moved on even if 10.0 hasn’t
The 10.0 label now spans a huge stretch of Windows development, while the names and numbers attached to Windows updates keep changing. The OS build is a much better way to distinguish modern Windows releases.
As of August 2026, Microsoft lists Windows 11 24H2 as build 26100 and 25H2 as build 26200. The newer Windows 11 26H1 release, aimed mainly at new devices rather than as an in-place feature update for existing 24H2 or 25H2 PCs, uses build 28000.
You can see the same pattern in Microsoft’s developer tools. Windows SDK releases still use version numbers such as 10.0.26100.x and 10.0.28000.x, while applications can target specific Windows releases and check at runtime whether newer APIs are available. At that level, the 10.0 prefix tells you very little about which modern Windows release you are actually dealing with.
That leaves Windows with a slightly ridiculous-looking version stack. “Windows 11 25H2, version 10.0, build 26200” can all describe the same operating system, with none of those numbers being wrong. They just refer to different layers of Microsoft’s versioning scheme.
For ordinary troubleshooting, that means the 10.0 prefix is not especially useful on its own. The product name, feature-update version, and OS build give you a much clearer picture of what a PC is actually running.
And the platform covered by that 10.0 label has changed a lot. Windows 11 introduced different hardware requirements, security baselines, shell components, APIs, servicing changes, and years of new features across successive builds. Treating the shared major version as proof that Windows 11 is just Windows 10 with rounded corners gives one old version field far more significance than it deserves.
Windows keeps its receipts
I like this quirk because it feels like such a classic piece of Windows archaeology. Microsoft can redesign the Start menu, raise the hardware requirements, ship years of new builds, and move all the way to Windows 11 26H1 while one number buried underneath everything still calmly reports 10.0.
Most people will never have a reason to care about what NT major version their PC reports, which probably explains why Microsoft has never bothered to chase perfect numerical neatness. Windows has a long habit of carrying ancient features and old technical decisions into newer releases, and sometimes all it takes to uncover one is a single command.