When will Microsoft pull the plug on your version of Windows or Office?

For the next year or so, Microsoft will officially offer support for four versions of Windows for desktop and notebook PCs.

Windows XP, the oldest of the bunch, celebrates its 12th birthday this fall. It kicks off a year-long farewell tour next week, counting down to April 8, 2014, when Microsoft officially ends its support. XP lived longer than any version of Windows ever, getting multiple extensions on its retirement date to placate customers who said no to Vista. But April 2014 is the end of the road.

XP will not get a last-minute reprieve.

Let me say that again, in boldface this time: Microsoft will not extend the support deadline for XP. If you're still relying on XP, you should have a plan to switch to a supported platform, whether it's from Microsoft or someone else.

April 8, 2014 is a deadline, not a death sentence. PCs running XP will not stop working when the clock runs out. In fact, XP diehards won’t notice anything different except an eerie quiet on Patch Tuesday. Newer Windows versions, including Windows Vista, Windows 7, and Windows 8, will continue to get security patches and bug fixes via Windows Update, but not XP. When the extended support period ends, so do those updates. (Large enterprise customers who have custom support agreements with Microsoft and who are willing to pay dearly for the privilege might be able to get custom updates after the official end of support. But consumers and small businesses will not have that option.)

None of this should be a surprise. As I’ve noted before, Microsoft has a well-established support lifecycle for its software products. It’s basically an agreement that the company makes with everyone who commits to Windows. The terms of that agreement don’t change often, which is an important assurance for business customers who tend to be conservative in their approach to upgrades.

Six months after the launch of Windows 8, it’s become obvious that Windows 7 is the new Long Term Support version. And I'm starting to get more questions from readers who are concerned that Microsoft is going to try to kill off Windows 7.

In a word: Relax. It’s not time to start a “Save Windows 7” movement yet. I've put together a chart listing the end-of-support dates for all supported versions of Windows and Office. Here’s the full list, which is accurate as of April 4, 2013.

* Chart updated since original publication with dates for Office 2013, as published here.

For all of those products, Microsoft provides at least five years of mainstream support, followed by another five years of extended support. These lifecycles apply equally to business and home versions of Windows and Office. Service packs have separate end-of-support dates. For example, beginning next week you’ll need to be running Service Pack 1 to get support for Windows 7. (There’s an exhaustive FAQ if you want to dig deeper into this stuff.)

Generally, “supported” means you have access to at least one type of assisted support option (possibly paid) and no-charge security updates through channels like Windows Update and the Download Center.

The calculations start with the general availability (GA) date for each product. The official date of retirement for support is the second Tuesday in the first month of the quarter following that anniversary (which also happens to be Patch Tuesday). That grace period typically means a few weeks or months of extra support tacked on at the end of the five- and ten-year support cycles for each product.

For Windows 7, you can do the math yourself. The GA date for all Windows 7 editions was October 22, 2009. Five years after that date is October 22, 2014. The next calendar quarter begins in January, 2015, and the second Tuesday of that month is January 13. So, that's when mainstream support is scheduled to end. Extended support for business all editions goes an extra five years, until January 14, 2020, which happens to be the second Tuesday of that month. (Those calculations don't work for Windows XP, whose end-of-life date was extended artificially.)

To find the end-of-support date for any Microsoft product, use the  Microsoft Product Lifecycle Search page, the product family index, or the full A-Z product index to get the official answer. When you find the entry for a specific product, you can see the general availability date, the retirement dates for mainstream and extended support, and retirement dates for service packs.