Where can I find default Microsoft fonts Calibri, Cambria?

If I want to test or use default Microsoft fonts on my Mac, and I own a post-2006 copy of Windows or Office, I believe I can legally use Calibri and Cambria although IANAL. This would be especially helpful when collaborating with colleagues using Office products like Word, Excel, and PowerPoint. Right now, I get a warning like: "Calibri not found. Trebuchet MS used instead." Where can I find them?

To find and install default Microsoft fonts on a Mac:

1. Navigate HERE in your browser.
2. Download the .ZIP file.
3. Unzip it (double-click it).
4. Open the folder that appears.
5. Select all the .TTF files inside the folder.
6. With the files selected, right-click.
7. From the pop-up menu, choose "open with → Font Book".
8. Click "Install Font" for each font.

Note: Changes to fonts take effect when an application is opened or a user logs in to the account or computer on which the changes occurred, see support.apple.com.

If you have local Microsoft Word installation, say in /Applications, you can find the bundled fonts in the locations below:

• /Applications/Microsoft Word.app/Contents/Resources/DFonts
• /Applications/Microsoft Word.app/Contents/Resources/Fonts (for earlier versions)

The same should apply to other Office applications as well. Then you can copy the fonts to:

~/Library/Fonts

BTW, in Finder, there's Go > Go To Folder...(⇧⌘G), which can be used to quickly navigate to a specific location.

If you use homebrew, try the homebrew-fonts-nonfree tap

Use the official Fonts distributed by Microsoft

If you have installed any Microsoft product, there is a chance you already have all Microsoft Fonts in your Mac.

For instance, the path to the fonts of MS Word is:
"/Applications/Microsoft Word.app/Contents/Resources/Fonts"
In general:
"/Applications/some_ms_app/Contents/Resources/Fonts"

Using terminal, you can copy any font to your font folder: ~/Library/Fonts

Below, the step-by-step instruction in case you are not familiar with terminal:

1. Open Finder and go to the Applications Folder (SHIFT+CMD+A)
2. Locate MS Word or MS Excel or MS PowerPoint.
3. Right-click and select Show Package Content.
4. In Finder navigate through Contents/Resources/Fonts.
   You will see all the installed MS Fonts.
5. Drag and Drop (press the Option key) the desired fonts to your Desktop (or any other user folder).
   You must press the option key to create a copy of the fonts and not a link.
6. Select (in your Desktop) the fonts to install. Right-click and then Open.
   The "Font Book" Application will check the fonts and probably it will give you some warnings.
7. Select the fonts in Font Book app and click Install.
8. Delete the extra copies you have in the Desktop.

Do not try to install right from the application package or you will receive a fatal error. That is why in 5. you must make a copy to some user folder (ex. your Desktop)