Try this small UDF:

Function divergence(r1 As Range, r2 As Range) As Integer
v1 = r1.Value
v2 = r2.Value
divergence = 0
i = Application.WorksheetFunction.Max(Len(v1), Len(v2))
For j = 1 To i
ch1 = Mid(v1, j, 1)
ch2 = Mid(v2, j, 1)
If ch1 = ch2 Then
Else
divergence = j
Exit Function
End If
Next
End Function

If the two strings exactly match, it will return a zero. It will also catch
case changes as well.
--
Gary''s Student - gsnu2007i


"Greg Lovern" wrote:

I have two strings that start with the same characters, but at some
unknown and varying point they begin to differ. I want the position
number of the first non-matching character.

For example:
-- table and chair
-- table plus chair
-- position of first non-matching character is 7 (the "a" in
"and", and the "p" in "plus").

In the above example, both strings start out "table ", then start to
differ beginning with the 7th character. How can I return the position
of the first non-matching character, which in this example is 7?


Thanks,

Greg