Claude: The payment should be 160.70 (you divide the interest by 12, not 24 as the rate is based on annual calculation, not the duration of the loan.)

Here is the algorithm:

inv = 3500.00
i = .095/12
n = 24
pmt = ROUND(inv /((1-((1+i)^-n))/i), 2)

HTH

>We have an old FoxPro for Dos program that uses the Payment function, The original Developers are long gone. The user would to know how the calculation is done. Syntax is
>
> payment = PAYMENT(loanamount,interest/payment, numberofpayments)
>
>For example if loanamount is 3500, interest is 9.5, and number of payments of payments is 24 then interest is .095/24 and payment is 153.16.
>
>Home is this caluclated?
>
>Any help appreciated.