=DATEDIF(A1,TODAY(), "y").

if Cell A1 = 08/15/1947 (MM/DD/YY Format)
I want to calculate the exact month. Above function is not working. Please help.

The formula you've shown is set to show YEAR differences, that's what the "y" flag accomplished.

If you want the number of months between the two dates, change that to "m".

If this still isn't what you want, provide a more complete example problem.

Date1 in cell A1
Today's date is??
Expected result would be: _________ (and why)