Microsoft Office 2016 and 2013, like all versions of Office and most other programs you pay for, requires that you enter a unique product key during the installation process, proving, to a point, that you own the software.
So what do you do if you need to reinstall the program but you've lost this important, 25-digit installation code?
You've probably already tried all the expected "looking around" but there are a few more things you can try that you may not have known about.
If you're familiar with product keys and how they work, you might assume that the Office 2016/2013 product key is stored, encrypted, in the Windows Registry, like older versions of Office and most other programs do.
Unfortunately, Microsoft changed how they handled Microsoft Office product keys beginning with Office 2013, storing only part of the product key on your local computer.
Important: The following should work if you're just looking for the product key for one member of an Office 2016 and 2013 suite, like Word or Excel, as well as if you're after the key for an entire suite, like Office Home & Student, Office Home & Business, or Office Professional in 2016 or 2013 versions.
Here are the 3 best ways to go about digging up a lost MS Office 2016/2013 product key:
If you purchased Microsoft Office 2016 or 2013 in a box with a disc, or as a product card (digital download) from a retail store, then your product key will be with that physical purchase - on the product card, on a sticker, on or in the manual, or on the disc sleeve.
If you purchased one of these versions of Office from Microsoft online, your product key is stored in your Microsoft account online (more on that below) and/or arrived in your email receipt.
If Office 2016 or 2013 came preinstalled on your computer when you purchased it, your product key should be printed on the holographic sticker attached to your computer.
Be sure you use the Office 2016/2013 product key and not the Windows product key that's probably also on that sticker.
My guess is that you've looked those places already before finding yourself on this page. However, there's one thing that might help you out, especially if you bought Office online:
While I mentioned already that product key finder tools won't find your Office 2016/2013 product key, some will locate the last five digits, the only thing stored on your computer, which can be helpful in your search.
Here's how to do it:
Obviously that trick isn't helpful if you don't have a digital paper trail of your Office purchase, but it's worth the trouble if you might.
If you previously registered and activated your copy of Microsoft Office 2016 or 2013, you'll be happy to know that Microsoft has stored for you, and will show you, your original product key.
Here's what you need to do to view it:
If that works, record your Office 2016/2013 product key and keep it somewhere safe. No need to repeat all of this again next time you need it!
Another option, that you may or may not have the most luck with, is to contact Microsoft directly to ask for a replacement key.
Microsoft obviously isn't going to just trust that you bought MS Office and read you a valid product key over the phone. You'll need to find whatever proof of purchase you can find and have it ready before calling.
You can find the best number to call on the Microsoft Support: Contact Us page.
If you have a copy of MS Office 2016 or 2013 installed on your computer that you installed via your Office 365 subscription, you don't need to worry about product keys at all!
Just sign in to your Office 365 account online and follow the menu prompts to download and install the latest version of Microsoft Office 2016.
Check the Using product keys with Office 365, Office 2016, or Office 2013 Microsoft Support page.