Highlighting Cells Containing both Letters and Numbers

Emmanuel would like to know how he can use conditional formatting to highlight a cell if that cell contains a mix of both numbers and letters. If the it contains all letters or all numbers, the cell should not be highlighted.

In this tip I won't focus on how to create a conditional format; there have been plenty of other ExcelTips that focused on that task. What I will focus on is a few formulas you could use in defining the condirtional formatting rule. The formula needs to examine the value in the cell and return "True" if it contains both letters and numbers, and "False" in all other instances.

Here are three different formulas you can try in the rule:

=SUM(IFERROR(FIND(ROW($1:$10)-1,A1),))*ISTEXT(A1)
=AND(ISTEXT(A1),MATCH(FALSE,ISERROR(1*MID(A1,ROW(INDIRECT("1:15")),1)),0))
=AND(SUM(--(ISNUMBER(--MID(A1,ROW(INDIRECT("A1:A"&LEN(A1))),1)))),ISTEXT(A1))

Any of these formulas work just fine (I would personally choose use the shortest one—less typing!), but there is one potential drawback. If you have numeric digits stored in a cell and the cell as formatted as Text, then the formulas will still return "True" and the conditional format is applied. This occurs because each of the formulas use the ISTEXT function, which looks at the format of the cell to see if it contains text.

The easiest way to get around this potential "false positive" is to create a user-defined function (a macro) that can then be referenced in your conditional formatting rule. Here's a very simple UDF that returns "True" only if the cell contents (not its format) contain both letters and numbers:

Function CheckChars(r As Range) As Boolean
    CheckChars = False
    If r Like "*#*" And UCase(r) Like "*[A-Z]*" Then CheckChars = True
End Function

In order to use this in your conditional formatting rule, simply use this formula:

=CheckChars(A1)

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (13422) applies to Microsoft Excel 2007, 2010, 2013, 2016, 2019, 2021, and Excel in Microsoft 365.