Symbols missing in equations converted from Word's equation editor to MathType

The information on this page applies to:
  • MathType for Windows
  • MathType for Mac
All supported versions of Word for Windows and Mac

You're working with a Microsoft Word document, and in the document are several equations created with Word's equation editor. You want to convert these equations to MathType equations. When you use the Convert Equations command on the MathType tab in Word, you don't get any pop-up error messages, but you notice some symbols are missing from the converted equations.

For example, when you convert this equation:

Sample equation from Word
this is the result:
Previous equation converted to a MathType equation

This one:

Another sample Word equation
converts to:
Previous equation converted to a MathType equation

Word's Equation tab has its own set of symbols that should be, and in some cases must be, used when creating equations in Word (also called "OMML equations"). The author of the equations shown above used the Insert Symbol dialog (from Word's Insert tab) to insert the Greek letters. Such symbols may look the same or similar, but they are encoded differently within the Word document and MathType cannot interpret them the way the author intended. This is not a bug in MathType nor Word. Rather, it's an example of symbols being inserted incorrectly into the equations or an incorrect symbol being used.

Rule number 1: Do not use Insert Symbol to insert symbols into OMML equations. Use only symbols from the Symbols group on the Equation tab:

and structures from the Structures group:

Rule number 2: When using symbols from Word's Symbols group, be sure to take note of the group of symbols your chosen symbol is coming from and note also the symbol's name. Let's illustrate with an example…

One symbol that's common for authors to choose incorrectly is the dot symbol often used to represent multiplication – this one: ·

The most commonly-chosen incorrect symbol for multiplication is this one:

bullet operator

Notice though, if I hover the mouse pointer over the symbol, Word magnifies the symbol and gives me its official name:

bullet operator is enlarged and identified by name

If you use that symbol in an OMML equation, it looks like the proper symbol for multiplication, but if you convert that equation to a MathType equation, it looks goofy. Compare before (left) and after (right):

OMML equation with bullet operator
Previous equation converted to MathType; bullet operator is too large

Yes it looks goofy, but MathType is merely being faithful to what the author asked for, which was to insert a bullet operator into the equation. For the correct symbol, this takes us back to the first half of rule number 2, which we haven't covered yet. That is, "take note of the group of symbols your chosen symbol is coming from". If you click dialog expander button in the lower right of the array of symbols, you can choose from 8 different groups of symbols: Basic Math, Greek Letters, Letter-Like Symbols, Operators, Arrows, Negated Relations, Scripts, and Geometry.

The symbol we're looking for is clearly an "operator", so let's choose Operators from the list. When we do, we're presented with a rather intimidating array of operators – 173 of them to be exact! Fortunately it's easy to see a couple of dots in the group labeled Common Binary Operators that look like what we're after:

Word's list of 19 common binary operators

Now we have another choice. There are two near the middle of that group, and both of them look identical! Good thing we already know to hover the mouse over them for their title. By doing so, it's easy to see the one we want is the one on the right – the Dot Operator:

Choose the dot operator from the array of symbols.

Now let's compare. In the table below, the top left is the unconverted bullet operator, top right is that equation converted to MathType, lower left is the unconverted dot operator, and lower right is that equation converted to MathType. Notice the nearly-identical appearance of the 2 unconverted operators:

OMML equation with bullet operator
Previous equation converted to MathType; bullet operator is too large
OMML equation with bullet operator
Previous equation converted to MathType; bullet operator is too large

That one at bottom right looks pretty good.

Moral of the story

Simple – do not use Insert Symbol to add symbols to OMML equations, and when you choose symbols from Word's palette of equation symbols, be sure what you use is the one you intend to use. Sometimes symbols look nearly exactly like a similar symbol, but the two symbols will have completely different meanings, and this may make a big difference if you later convert the equations to MathType or to a language like LaTeX or MathML.

It's important to note if you mistakenly created OMML equations using the wrong techniques as described above, or if you're working with a document from another author and that author created the equations, there's nothing you can do to "fix" the OMML equations except to replace the symbols with symbols you insert properly. Likewise, there's nothing you can do to fix the converted MathType equation except to add the missing symbols manually.


We hope this has been helpful. As always, please let us know if you have questions about this, or if you have additional techniques that work. We'd love to hear from you.