Is it your aim just to establish whether the cell contains a comma, or do you want to do something with that information?

Perhaps there's a better way to achieve your ultimate objective.

btw, as you may have noticed

=FIND(",",A1) will give a #VALUE! error if A1 doesn't contain a comma

my suggestion, which returns TRUE (if there is a comma) or FALSE if not

=FIND(",",A1&",")<=LEN(A1)