I often create various tables in Excel. When I do so, I often like to highlight missing values from the table. Typically, I put in a question mark ? in the cells in which I am missing values. In order to highlight them, I like to use Excel Conditional Formatting.

Problem is, however, that ? has a special meaning in Excel. It is used as a wildcard that will match all cells containing at least one character.

Thus, the question mark must be escaped in order to use it in a conditional formatting rule.

I tried all kinds of weird escaping methods and finally found one that works: Prefix the question mark with a tilde:

~?

The tilde can be used to escape other wild card characters such as *.