This article has your answer. Note specifically the section that says this (the previous sections are important, too):

Determine the position of the number in the alphanumeric string

Now we determine the position of the number by locating a TRUE value in the result of the decomposed string mentioned in the paragraph above. We employ the MATCH function here. The revised formula now becomes:

=MATCH(TRUE,ISNUMBER(1*MID(A1,ROW($1 :$9),1)),0 )

Important: You must enter this formula as an array by pressing CTRL+SHIFT+ENTER. If the string is abc123, this formula will yield 4 — that being the position of the first numeric character in the alphanumeric string.

There's more in the article after that, but this is where you can stop. :) Regards, Joe