Warning: Excel provides the DATEDIF function in order to support older workbooks from Lotus 1-2-3.The DATEDIF function may calculate incorrect results under certain scenarios. Please see the known issues section of this article for further details.

Add an email address or phone number to your Microsoft account and keep your current contacts, online storage, subscriptions, and account settings.

Learn how to change Microsoft account email address or phone number using aliases to sign into your Microsoft account.

Change or set the default font in Outlook to use whenever creating new messages.

Find out which power supply model goes with your Surface device—including the power supply model number, power and wattage, and USB charging port.

Learn about the UNIQUE function, which returns a list of unique values in a list or range. UNIQUE is in a class of functions called dynamic arrays.

Add or edit hyperlinks to web sites, local files, email messages, or anchor points in your document.

Learn how to recover a hacked or compromised account, what to do next, and how to prevent your account from being compromised in the future.

Find out how to change your Xbox gamertag through a browser, on your Xbox console, or your Windows device.

By importing a snapshot of your Google calendar into Outlook, you can see it alongside other calendars in the Outlook Calendar View. To keep the imported calendar up-to-date, subscribe to the Google Calendar in Outlook.