How to Calculate a 15 Year Mortgage
- 1). Add 1 to the monthly interest rate, expressed as a decimal of the mortgage. For example, if the monthly mortgage rate equals 0.0065, you would add 1 to get 1.0065.
- 2). Multiply the result from step 1 by itself 180 times. This equates to the 180 payments you will make during the 15-year term of the loan. In this example, you would multiply 1.0065 by itself 180 times to get 3.209816908.
- 3). Subtract 1 from the result from step 2. In this example, you would subtract 1 from 3.209816908 to get 2.209816908.
- 4). Divide the monthly interest rate by the result from step 3. In this example, you would divide 0.0065 by 2.209816908 to get 0.00294142.
- 5). Add the monthly interest rate to the result from step 4. In this example, you would add 0.0065 to 0.00294142 to get 0.00944142.
- 6). Multiply the result from step 5 by the amount you borrowed. In this example, if your mortgage was $396,000, you would multiply $396,000 by 0.00944142. This calculates your monthly payment to be $3,738.80.
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