How to Calculate a Loan Payment
Start by entering the amount of the loan into a calculator.
If you're going to make a down payment, and you know the dollar amount of it, subtract it from the loan amount. If you only know the percentage of the down payment, calculate the dollar amount this way: take the percentage and divide it by 100, then multiply that number by the amount of the loan.
Deduct any down payment you may have from the loan amount.
To find out your monthly payment, you must know the length of the loan and the interest rate. It is then a good idea to enter this information into a loan calculator (try the one in the resources section), because the math becomes awfully complex to do on your own at this point.