You don't really need to use ISNUMBER.

For case consideration

=FIND("M",A1)

Or, for case not a consideration:

=SEARCH("M",A1)

FIND/SEARCH will return either a number =1 or an error. When the return is
any number other than 0 the format will be applied. When the return is an
error the format will not be applied.

--
Biff
Microsoft Excel MVP


"Sheeloo" wrote in message
...
OR use in FORMULA IS
=ISNUMBER(FIND("M",A1))

or

=ISNUMBER(FIND("M",UPPER(A1))) if you want both m and M.

"Teethless mama" wrote:

Assuming you're looking for a letter "e"

Select your range

Conditional Formatting:

=COUNTIF(A1,"*e*")



"JDesmarais" wrote:

I want to format the worksheet to look in every cell for a letter and
if that
letter is present, color the background a color. I cannot figure out
how to
write the formula to search the entire worksheet without turning the
entire
worksheet the color.

Example, everytime a cell's entry is M color the background green