The short answer is you need to buy a new font. Out of the box, Office 2010 and 2013 have only Cambria with all of the math characters that are needed for the Equation Editor. You can verify this is also 
your circumstance by clicking expand link at the bottom right of the TOOLS box in the EQUATION EDITOR > DESIGN tab (see the screen shot to the right)
After some considerable effort, I have still not found a compatible font so I have posted this with Microsoft Partner Support and after some back and forth, this is what they said:
…Cambria Math is the only supported font that can be used in Equation Editor in Word 2013 for the time being. Anyway, the DEFAULT FONT is a drop down box and it will have alternates after some improvements are made by the developing team.
A slightly longer answer is the work around of forcing your equation to “NORMAL TEXT” (see the screen shot to the right). The tells Word that you you are not writing math, just normal text which will then allow you to change the font at will. The risk here is that you will lose characters because they don’t exist in your new font (say Arial).
11 Comments
Natee · January 26, 2020 at 6:03 am
“erewhon-math” This Math font works well with Utopia. Originally, it is the same font used in Fourier Package.
https://ctan.org/pkg/erewhon-math
Brenton · May 10, 2018 at 3:35 pm
In addition to the typefaces listed by Shay Riggs, there are also Latin Modern Math (the LaTeX typeface) and GFS Neohellenic Math and Fira Math (two beautiful sans serif math fonts).
Shay Riggs · April 11, 2018 at 4:23 am
To use the “new” equation editor, you need a font that contains the appropriate OpenType Math features. On Windows this should just be a case of right-clicking the font in Explorer and selecting “Install”, or dragging it into the Fonts folder.
I quite like the new EE although it is not without its quirks, such as when you choose a template it doesn’t put the cursor inside it so you can type right away, but right after it.
I’m sure you could still access the original equation editor (although it’s missing on my Office 365) via the Insert » Object » Microsoft Equation 3.0.
Let’s face it though: if you are doing anything containing complex mathematics, you’ll probably be using LaTeX or whatever anyway…
Others have noted the common ones in earlier comments – here are some free ones:
– Asana Math
– STIX (very early OT math font)
– XITS (STIX revised by some TeX users)
– TeX Gyre math fonts (a quite nice range of fonts that match the old PostScript standards such as Times, Avant Garde, Schoolbook, Palatino; they all come with complete families of matching text fonts too)
There are also a couple of commercial ones, all of which work nicely with Word:
– Cambria Math (comes with recent Word versions)
– Lucida Bright Math OT (very nice, and has a bold version too)
– Minion Math from Typoma (also very nice, but expensive [~€700] if you want the complete family of 20 [!] weights and optical sizes, most of which you’re never likely to use; thankfully you can get the just “Regular” alone for around €80)
As with any commercial software, only you can know whether it’s worth the money or not.
Recently (Easter 2018) I’ve heard about STIX2, which is a completely overhauled version of the original STIX fonts:
https://www.overleaf.com/blog/623-opentype-based-math-typesetting-an-introduction-to-the-stix2-opentype-fonts
Have fun!
Dom · April 11, 2016 at 10:35 pm
There is a way, but it requires to manually modify the registry.
Download one of the following fonts and install them:
XITS Math: https://github.com/khaledhosny/xits-math/downloads
Latin Modern Math: http://www.gust.org.pl/projects/e-foundry/lm-math/download
Asana Math: http://www.ctan.org/tex-archive/fonts/Asana-Math/
Open the registry with “regedit.exe” and change the following values:
BE SUPER CAREFUL!!!
[HKEY_CURRENT_USER\Software\Microsoft\Office\15.0\Common\MathFonts]
“Cambria Math”=dword:00000001
“XITS Math”=dword:00000001
“Latin Modern Math”=dword:00000001
“Asana Math”=dword:00000001
Finally, do the steps shown on this webpage. There will be more than a single option.
New MS Word User · February 19, 2016 at 6:28 pm
It is possible. Edit the equation first using the default font which is Cambria Math. Then type in a character selecting “normal text”. Now change the font of that character. Then cut and paste it over the Cambria Math character. It works!
Suleiman · March 3, 2015 at 8:09 am
In Word 7 or Word 10 use the Word 3 equations editor instead. Click insert and then object. Choose microsoft 3 and you are on your way.
Appa · March 20, 2014 at 3:58 am
How come the newer versions have less features than the older ones. Only with Microsoft!
Ian Matthews · March 30, 2014 at 4:21 pm
I suppose time marches on and some features are dropped. I just confirmed that under SP1 for Office 2013 the same limitation of not being able to change the font still exists.
appa · April 17, 2014 at 3:58 pm
I agree – but it’s very annoying when changes are regressive, not progressive.
TeX User · August 6, 2013 at 1:59 am
You may look up for some font such as XTIS Math font, or Asana Math font. These fonts can be used with microsoft equation. 🙂
SW · July 8, 2013 at 4:37 pm
Try searching for Asana Math.