Sum row values based on a start month, and number of months

[Scott Emmanuel]

Greetings,

There must be a simpler way with a formula...Trying to sum a row of values based on a start month, then a number of months following that would be entered by the user - would include the start month.

Thanks for any assistance.

[Mazzaropi]

Scott Emmanuel, Good evening.

Try to use this formula:
=SUMPRODUCT(($E$4:$W$4>=B5)*($E$4:$W$4<=DATE(YEAR(B5),MONTH(B5)+C5-1,DAY(B5)))*(E5:W5))

Please, take a look at this example and tell us if it worked as desired.

I hope it helps.