Instead of creating a date & time column with Today's date as default value, create a calculated column directly using below formula:
=DATEDIF([Start Date], TODAY(), "Y")
Documentation: Calculated Field Formulas
Useful thread: How to use Today and Me in Calculated column
Sometimes comma(,) does not work in formula (I am not ...
Looks like you simply need to put "n/a" into the FALSE parameter of the IF statement. I assume that you are aware of the IF() syntax, i.e.
IF(<condition>, <do when true>, <do when false>)
So, for your formula that would be
I've also removed the ...
I just tried the same steps as given below & it works for me:
Create a calculated column with formula (with return type as Single line of text).
=IF(MONTH(NOW()) = MONTH([DateField]), "Yes", "No")
Where DateField is my date column.
Edited existing view with below filters:
Original list (All items):
Output - Filter list view:
Your formula seems incorrect. If you notice the difference in dates
9/1/2021 - 9/21/2021 = -20 but your screenshot is showing -19.
Try using this formula below