Hello all - I've been trying to create a program that prequalifies somebody for a loan (or at least gives me a read on whther they will or not).

The problem I'm coming across is that the math isn't entirely working out.  If any of you fine Sesame users are working on similar projects, maybe you could give me a hand. ---

The main problem is amortization - this is what I've BEEN using as my code:

===============
if main_term > 0 AND
main_interestrate > 0 THEN
{
PMRP_MPI =
(MAIN_loanamount*((@EX(1+(MAIN_interestrate/12)),(main_TERM*12))*
(main_interestrate/12))/((1+@EX((main_interestrate/12),
(main_term*12))-1)))/1000
================

I finally got it to where it wasn't dividing by zero, but now I can't seem to get it to process the number correctly.  The idea is by the person punching in the LOAN AMOUNT, THE INTEREST RATE, and the TERM, they should get an amoritized monthly payment. 

Anyone have a tip?

Thanks for the quick response, but here's the problem.  The @PMT isn't Amortirizing.

ie:

For sake of ease in trying to figure this out, I've made a small program.  4 fields.

MAIN_LOAN
MAIN_RATE
MAIN_TERM

The programming for MAIN_MPI reads:

main_mpi = @PMT(MAIN_LOAN,MAIN_RATE,MAIN_TERM)

I've also tried (MAIN_RATE/MAIN_TERM), (MAIN_TERM*12)

Nothing seems to change it from doing the basic math withou the more complex amort stuff.


Thanks for your continued help.
James

Ray,

example would be 100,000 loan
                              6% rate
                              30 year or 360 months
                              payment should be 599.55
any help would be appreciated

glenn and james

Quote:



For compatibility purposes, Sesame's @PMT function works identically to the one in Q&A. By converting the 6% APR to a monthly rate, I get $589.37. However, this differs slightly from your number.

I looked up the formula used by the online calculators (which match your numbers). By using this formula in SBasic, I was able to match the results provided by an online mortgage calculator.

Function CalcPayment(vRate as Double, vMonths as Double, vPrincipal as Double) as Double
var vPmt as Double
var vInterest as Double


	vInterest = (vRate / 1200)
	vPmt = (vInterest + (vInterest / (@EXP(1 + vInterest, vMonths) - 1))) * vPrincipal
	Return(vPmt)

End Function 

So, the following line of code would print the result you expect.

WriteLn(CalcPayment(6, 360, 100000)) 

If you want to see the math, the formula is available here:
http://www.1728.com/loanform.htm