newbie question about financial calculations

[Stephanie S]

Hi. I have an Excel workbook which is used by some folks in our office.
Every once in a while, they ask us in the IT department to change something
on it. The person who wrote it did so as an assignemtn for a class. And now
I have the pleasure of figuring this out. Anyway, I am pretty bright. I
should be able to do it. The problem is that it is about a loan calc. I know
nothing about loans. What I have is this. The user enters

Amount Borrowed
Interest Rate
Monthly Payment

And the sheet calculates the term using

=IF(ISERROR(NPER(D8/12,-D10,D6,,1)),0,NPER(D8/12,-D10,D6))

Where
D8 is the interest rate
D10 is the Monthly Payment
D6 is the Amount Borrowed

The user would like to also calculate the Total Interest Paid. I have no
idea how to do this. I went to help and looked at the list of financial
functions. I cannot tell which one(s) might help me.

Anyone willing to give me a push, maybe point to a couple of functions which
might work?

Thanks

S

 

[jr]

This function calculates the number of payments made on a
given principal at a given interest rate (in this case
compounded monthly - hence interest divided by 12).
The user selects the amount of the payment so the payment
amount times the value of the NPER function is the total
amount paid.
The total paid minus the principal is the interest paid.
This is outlined quite clearly in the help areas for
functions.
Hope that helps.