When you want to determine payments on a fixed rate mortgage, you'll need the interest rate and length of the mortgage. The easiest way is to enter the length of the mortgage and the interest rate into one of the specialized mortgage calculators available online. If you'd rather do the math yourself, though, a basic calculator is all you need.
Calculate the length of the mortgage in months by multiplying the number of years by 12. A 10-year loan is 120 months long.
Divide the loan's interest rate by 12 to determine the monthly interest paid. If the interest rate is 4 percent, or 0.04, divide 0.04 by 12. The result is 0.0033.
Multiply the monthly interest by the amount of the mortgage. Record this number, which is called "the numerator." You'll need it later.
Add 1 to the amount of the monthly interest rate. For example, if the monthly interest rate is 0.0033, add 1 to that. The result is 1.0033.
Find the key on your calculator that allows you to calculate "y to the power of x." Enter "0" minus the number of months of the loan -- in this case 120. The result would be 0.033 to the power of minus 120. This is called "the denominator."
Divide the numerator by the denominator. The result, rounded to the nearest hundredth, is the monthly payment.
Items you will need
- Mortgage information
- NA/AbleStock.com/Getty Images