Start date and end date

Sergei,

Thanks for your help and please excuse my lack of knowledge, but I have never used this type formula before. I entered the end date calculation as you suggested, but it brings back a date format answer. I probably didn't explain correctly in my initial post, but the aim of the sheet is as follows:

If for Income Source 1 in the Assumptions Tab, the start date is Jan'19 and the duration is 6 months, I want the net value in F9 to run from Jan'19 to Jun'19 inclusive within the 10 year cashflow. If the start date gets changed to Feb'19 and the duration is 7 months,. the value in Assumptions F9 will run in the 10 year cashflow from Feb'19 to Aug'19 inclusive....... and so on.

Is this possible? 

Thanks again.