Originally Posted by day92 :
Are you looking for something like this?
Well, that is the basic calcuation, yes. However I'm trying to do a more complex and exact calculation. When dealers contract people, they had something called days to first payment, usually it's between 30 and 45 days. Because of this, those simple interest calculators (like the one you posted) are calculating the term, but not the days to first payment, which cause all of the numbers to be incorrect. What I'm trying to do is get a calculation down to the penny. The problem I'm having is how to write the formula. I need to calculate the days to first payment, which is the contract date - first payment date, then I need to add all the additional payments in the term. However, if I do a simple day calculation, it causes problems because the payments always remain on the same day, when I try doing a daily calculation excel always seems
to calculate the final payment 6-10 days after the actual final payment date. I need to reverse the data on a contract to find out how I need to make a formula. Here is another contract for reference:
Contract Date: 4/29/11
All of the data is here to form the calculation but I can't seem to figure it out and it's really frustrating. X I know I will not get it perfect, because the dealership's systems do tend to have a very slight variance in the actual interest rate vs. the calculated rate, but regulation Z compliance allows some variance. I can't even seem to get within 500 bucks of the actual finance charge. I've just about given up out of frustration, I might have tried 100 different formulas. If anyone has the time or the interest to help, I would really appreciate it.
I think you need to find out how they calculate the daily interest rate from the annual rate.