Any Excel function that will reverse a string?

The current accepted answer is a poor way to reverse a string, especially when there is one built into VBA, use the following code instead (should act the same but run a LOT faster):

Function Reverse(str As String) As String
    Reverse = StrReverse(Trim(str))
End Function

There is no built-in function that I know of, but you can create your own custom function.

First - create a new module:

1. Get into VBA (Press Alt+F11)
2. Insert a new module (Insert > Module)

Second - paste the following function in your new module (Reference):

Function Reverse(Text As String) As String
    Dim i As Integer
    Dim StrNew As String
    Dim strOld As String
    strOld = Trim(Text)
    For i = 1 To Len(strOld)
      StrNew = Mid(strOld, i, 1) & StrNew
    Next i
    Reverse = StrNew
End Function

Now you should be able to use the Reverse function in your spreadsheet

I found an alternative that doesn't require VBA at https://exceljet.net/formula/reverse-text-string

The formula is

=TEXTJOIN("",1,MID(B5,ABS(ROW(INDIRECT("1:"&LEN(B5)))-(LEN(B5)+1)),1))

where B5 is the input cell.