Calculate minutes from an hour

=(b2-a2)*1440

formatted as a number instead of as time.

Times are just numbers, with the decimal part the fraction of the day that would have elapsed by that time, and the display is just a special formatting of that number. For example, noon is 0.5, 6:00 PM is .75 When you subtract two times, you get the fraction of the day between those two time - Noon to 6PM is .75 - .5, or .25. There are 24 hours in a day, and 60 minutes in each hour, so there are 1440 minutes in a day. To calculate the hours, you would multiply .25 by 24; for minutes, .25 by 1440.

Go to format cell and format your cell to [mm].

I would use the formula =C2 in D2, then format as elapsed minutes [m] or [mm] depending on how many digits to display. Number format codes: https://support.office.com/en-us/art...2-09fab54be7f4

Of course, you need to recognize that the actual cell value is still the date/time serial number stored in C2 (0.0944444 for 136 minutes). You will need to do something else if you want the actual value of D2 to be the number 136 and not a date/time serial number formatted as elapsed minutes.