-PMT Interest RatePayments per YearTotal Number of PaymentsLoan Amount0. The NPER argument is 3012 for a 30 year mortgage with 12 monthly payments made each year. The first step to calculating monthly mortgage payments is to convert the APR into a decimal fraction.
P L c 1 c n 1 c n - 1.
Heres a quick look at the formula to calculate a monthly mortgage payment on a. The formula does not differ based on what the money is spent on but only when the terms of repayment deviate from a standard fixed amortization. The rate is divided by 12 to get a monthly rate and the term in years is multiplied by 12 to get the total number of monthly payments nper. Convert Interest Rate into Decimal.