It's official. July 29 is the date that everyone can get Windows 10 for their PC — if they want it, that is — whether that's as a brand new operating system, or as a completely free upgrade from Windows 7, Windows 8, or Windows 8.1.
— Windows (@Windows) June 1, 2015
That date of July 29 is for Australia, too — we're one of 190 markets around the world that will see Windows 10 released simultaneously. If you're already running Windows 7 or 8, you'll have a year to upgrade to Windows 10 — so any time before the end of July 2016 — and Microsoft will continue to support Windows 10 for the lifetime of whichever PC you install it on.
Windows 10 looks pretty great, so we're excited to try it out as an official, complete product rather than just a developer preview. Fingers crossed the upgrade goes a little more smoothly than when Windows 8 came to town. [Microsoft]