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+--- Thread: Finance App TVM with irregular cash flows (/thread-16998.html)
Finance App TVM with irregular cash flows - Stefan Falk - 05-24-2021 05:36 PM
Hello everybody!
I am still in the process of learning the HP Prime with its overwhelming set of functionality. Up to now, I could not figure out how to calculate the loan for a bought house with additional payments. The finance app calculates well using just the monthly paid amount, but how do I calculate the plan if we pay additional amounts at different times (we are allowed to pay up to additional 5% of the total amount each year)?
Best Regards,
Stefan
RE: Finance App TVM with irregular cash flows - roadrunner - 05-26-2021 01:20 AM
I would do something like that with the spreadsheet app; like the one attached.
-road
[attachment=9505]
RE: Finance App TVM with irregular cash flows - Stefan Falk - 05-26-2021 06:55 AM
Thank you very much, roadrunner!
I'll try to get the hpapp into my prime.
Btw, do I remember correctly that the good old HP-92 desktop calculator could handle that, or was that "just" irregular cash flows in bond calculations?
Thanks again,
Stefan
RE: Finance App TVM with irregular cash flows - Stefan Falk - 05-26-2021 07:06 AM
Hello roadrunner again,
I tried your app and it seems to work fine. I had made an Excel sheet for the calculations, because the dates at which we paid the additional 5% varied from year to year.
Isn't there some built-in function accepting some array of dates and amounts in addition to the usual suspects such as PV, FW and so on? I could not find one yet.
Best Regards,
Stefan
RE: Finance App TVM with irregular cash flows - Albert Chan - 05-26-2021 11:20 AM
Hi, Stefan Falk
Welcome to the forum.
We could do it all in finance app, by pulling all extra payments into NPV
All we need is terms and rate, and the list of extra payments.
Example, loan is 5% APY, compounded monthly, terms is 30 years (N=360)
At N=2, extra payment of $1000
At N=20, extra payment of $2000
Finance app: I%YR=5, P/Yr=12, C/Yr=12, End=√, PMT=0
// shift N=20 payments to N=2
N=18, FV=2000 → PV=−1855.7761122
// shift N=2 payments to N=0, i.e. NPV
N=2, FV=1000-(−1855.7761122) → PV=−2832.12589423
// Spread NPV effect to regular payments
N=360, FV=0 → PMT=15.2034641912