Trip the formula and use msgboxs to show the current result...
Some thing like this:
Code:
Payment=(1 + RATE)* (-1) 'This should be the critic part, if you can pass this then all ok...
MSGBOX(payment)
Payment=(Payment+Rate) 'I don't know how you are implemeting the rate...But you should not introduce a percentage in a direct calculation...
MSGBOX(payment)
Payment = Payment * Principal
If I recal correctly, from my math lessons, multiplying by a negative number is equal to dividing by that absolut number(?)
Rate SHOULD not be in percentage, but represent the ratio...