Google Sheets – Calculate Time Difference Within One Cell

You need to split the content of cells, then do the math (using arrayformula) and finally join again:

=join(char(10), arrayformula(24*(split(D26, char(10))-split(C26, char(10)))))

Here char(10) is the "new line" control character.

The above will preserve the format of the original cells (e.g., time will remain time). Note that the final result (after join) is just a text string, which cell formatting will not change. If you need the result to be formatted as a number, do it explicitly with value:

=join(char(10), arrayformula(24*value(split(D26, char(10))-split(C26, char(10)))))

Remark. Putting two values in one cell is generally a bad idea if you plan to continue calculating with them. It's mostly a thing we do with text or with final output.

You need to use regexreplace first to remove the time part of the time stamp, and then the Text() function will properly transform the way you want.

=TEXT(REGEXREPLACE("date timestamp string","\d+:\d+:\d+",""),"MM")

Note: the timestamp part of the formula - may need to be altered depending on what exactly your string looks like, if you post an example of the string your starting with - I can modify the regex for you to fit that criteria

ALso if you share an example sheet - we can incorporate your DCOUNTA or a COUNTIF alternative