Windows11 Why is week number missing from the taskbar calendar

There's no setting for it - the taskbar calendar has never supported week numbers, and the Region date format workaround people suggest doesn't work either, since there's no week-number variable in the custom date format strings.

So it's third-party or nothing. Disclosure: I develop one of the options, ZefirCalendar, a tray calendar that shows ISO week numbers - https://apps.microsoft.com/detail/9P95DT1HKT15

Worth voting for it in Feedback Hub too. It's a small ask that keeps getting ignored because nobody files it.

There's no setting for it - the taskbar calendar has never supported week numbers, and the Region date format workaround people suggest doesn't work either, since there's no week-number variable in the custom date format strings.

So it's third-party or nothing. Disclosure: I develop one of the options, ZefirCalendar, a tray calendar that shows ISO week numbers - https://apps.microsoft.com/detail/9P95DT1HKT15

Worth voting for it in Feedback Hub too. It's a small ask that keeps getting ignored because nobody files it.

Use a sticky notes app or widget that displays week numbers.

The current Windows 11 taskbar calendar simply does not have a built-in option to show week numbers.
There is no supported registry setting or Group Policy that enables week numbers in the current calendar flyout. The screenshot shows the requested week-number column, but that layout is not available in the standard Windows 11 taskbar calendar.

For now, the practical workaround is to use Outlook or another calendar app that supports week numbers. In classic Outlook, this can be enabled under File > Options > Calendar > Display options > Show week numbers in the month view and in the Date Navigator.

Third-party tools that replace the taskbar or restore an older calendar may provide this feature, but they modify the Windows shell and can stop working after an update. A native option would need to be added by Microsoft, so this is worth mentioning in Feedback Hub.