Mortgage payment calculator
Enter the loan amount, interest rate and term: get your fixed monthly payment, the total interest you'll pay, and the first 12 months of the amortization schedule.
This is a rough simulation based on a constant nominal rate only: it does not include property taxes, homeowners insurance, PMI, closing costs or your lender's actual APR. This tool provides estimates only and is not financial advice.
How a fixed-rate mortgage payment is calculated
Most mortgages are fully amortized loans: you pay the same amount every month for the whole term. The payment comes from the formula M = P × i / (1 − (1 + i)−n), where P is the principal, i the monthly rate (annual rate / 12) and n the number of payments. Early on, most of each payment goes toward interest and only a small slice pays down the principal; over the years that ratio flips. That's why extra principal payments and refinancing save you the most money in the first years of the loan, when the balance is still shrinking slowly.
The last payment and the other mortgage tools
Here the payment is worked out to the cent, as a bank does: each month's interest is rounded to the cent, and the payment is the smallest one that clears the loan in the number of payments chosen. That is why the last payment, the one that brings the balance to exactly zero, is a little lower than the others: with 150,000 at 3% over 25 years it is 710.01 instead of 711.32, and the results box shows it under the figures. The same calculation, with the same code, is behind Amortization schedule, which shows every payment, Early repayment, which adds an extra payment each month, and Debt payoff time: entering there the payment found here gives the same number of months and the same interest.
Interest rate vs. APR: why your real payment may differ
This calculator uses the nominal interest rate, the number the payment formula is built on. The true cost of a mortgage is better captured by the APR, which folds in origination fees, points, appraisal costs and other charges, two lenders quoting the same rate can have very different APRs. On top of that, your actual monthly bill usually includes escrow items such as property taxes and homeowners insurance, and with an adjustable-rate mortgage the rate itself changes over time. This tool provides estimates only: it does not replace a lender's Loan Estimate or the advice of a qualified financial advisor.