The context for this question is that say I have 200 dollars locked up that will be paid back to me each month for a varying amount of money with the final payment taking pace on the 4th year. I’m trying to determine not the present value of the 200 dollars BUT rather the weighted average “lockup period”.

i.e.

1/31/2023 pay back $1 dollar 2/28/2023 pay back $0.5 …… 1/31/2027 pay back remaining $0.3

How do I calculate the weighted average of the “lock-up period” because intuitively since the money is being paid back to me, the lock up time period is not 4 years but rather should be weighted by the $ amount being paid back.

Should it be simply be: =sumproduct(Every date: Every $amount)/ sum(Every $amount)?