To calculate the monthly payment amount     Loan Amount  US$  Interest Rate  % Loan Period 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15  Years Payment-Frequenc y Monthly Monthly Payment Amount  US$ To calculate the monthly payment amount, simply plug in your numbers. Try other numbers as well to see what effects are produced by changing either the loan amount or the loan.