>Anyone know how to calculate the payment on a loan where the first XX months are interest free and the remaining months are charged interest? PAYMENT() doesn't work in that situation. I found a good site on loan calculations at http://oakroadsystems.com/math/loan.htm, but it doesn't cover that scenario.
>
>Thanks.

For every loan with some interest charge type,
the period payment is LOAN*function(interest rate,paymentsCount)
then:

L = 100000	&& LOAN
P = 12/100	&& ANNUAL INTEREST
M = 10*12	&& TOTAL PAYMENTS
N = 3		&& INTEREST FREE PAYMENTS
* x is unknown Payment
* bond
* x = SomePayment(L-x*N,P/12,M-N) = (L-x*N)*f(P/12,M-N)
* general solution
* x = L*f/(1+N*f)

* With VFP payment type:

R = PAYMENT(L,P/12,M-N)

x = ROUND(R/(1+N*R/L),2)

? m.x