NPV - 4 values over 60yrs

[Guest]

Hello,

I am trying to use the NPV function to look at 4 cash flows over a 60yr time
frame. There is an intial immediate cost, than cash flows at YR20, YR40 and
YR60. I am using a yearly discount rate of 8%. I was using the following
formula -> =NPV(.08*20, YR20, YR40, YR60) + Intial Cash Flow, but it didn't
match up when I compared it to performing the NPV at each point in time and
adding it up -> (=Initial Cash flow + (YR20 cash flow/(1+.08)^20 + ...). But
the NPV formula does come close when I add a 0 for Value1 -> =NPV(.08*20, 0,
YR20, YR40, YR60) +Intial cash flow.
Am I using an incorrect discount rate in the formula or using the arguments
incorrectly? I am just not sure how the 0 in Value 1 gets me close to the
actual NPV value.
Thank you for your assistance in advance.
-G

 

[Niek Otten]

If you post your inputs, results and expected results we could check any
advice we'd like to give

 

[Guest]

..08*20 doesn't consider compounding. Try (1.08^20)-1 as the periodic rate.
--Bruce