Focused calculator
Mortgage Payment Calculator
Estimate the regular principal-and-interest mortgage payment from the mortgage principal, entered interest rate, amortization period, and payment frequency. This calculator does not assess mortgage qualification or affordability, and it does not calculate a down payment or the other costs of buying a home.
What this calculator estimates
The calculator estimates the regular payment for the selected ordinary payment frequency. The payment includes mortgage principal and interest only. Property taxes, home insurance, condominium fees, utilities, and other ownership costs are not included.
Mortgage amount means the mortgage principal being modelled. It is not the home's price or the down payment. The result does not test affordability, mortgage qualification, or debt-service ratios.
How to use the calculator
Enter the mortgage principal, the nominal annual mortgage rate, and an amortization period that can be expressed as a whole number of months. Then select monthly, twice-monthly, biweekly, or weekly payments. The entered rate is held constant throughout the illustration.
The mortgage rate is the nominal annual interest-rate assumption used for this illustration. It is converted using semi-annual compounding. It is not a qualification rate, a forecast of a future rate, or a lender quote.
The mortgage term is the period during which a mortgage contract is in effect. The amortization period is the total time the repayment plan is expected to take. An actual mortgage usually spans several terms, and the rate and other terms may change at renewal.
The calculator treats monthly, twice-monthly, biweekly, and weekly payments as ordinary (non-accelerated) payment arrangements. The twice-monthly, biweekly, and weekly amounts are calculated from the unrounded monthly payment; the calculator does not add extra or lump-sum payments.
How the payment is calculated
- Convert the entered nominal annual rate, compounded semi-annually, to an equivalent monthly rate. Use that rate to calculate the monthly payment that amortizes the mortgage principal over the entered number of months.
- Use the unrounded monthly payment as the basis for all ordinary frequencies: use it as-is for monthly payments; divide it by 2 for twice-monthly payments; multiply it by 12 and divide by 26 for biweekly payments; or multiply it by 12 and divide by 52 for weekly payments.
- Convert the entered nominal annual rate to the corresponding periodic rate for the selected frequency. At the end of each payment period, calculate interest on the opening balance; the rest of the payment reduces principal.
- Continue the illustration until the mortgage is paid off. The final payment is limited to the principal and interest then owing, so it may be smaller than the regular payment.
- Keep unrounded precision in the calculation and display public currency amounts to the nearest cent. Multiplying a displayed rounded payment by the displayed number of payments may therefore differ slightly from a displayed total.
Because twice-monthly, biweekly, and weekly payments are calculated from the monthly payment rather than solved independently for the same final date, some frequencies may pay off the mortgage shortly before the entered amortization period ends. This is a modelling result, not an accelerated-payment recommendation.
Example
Suppose the mortgage principal is $500,000, the nominal annual rate is 5%, and the amortization period is 25 years. The estimated monthly principal-and-interest payment is $2,908.02.
For ordinary biweekly payments, the amount is calculated from the unrounded monthly payment × 12 ÷ 26, or about $1,342.17 every two weeks. Under the calculator's payment-period interest method, the mortgage is paid off with a smaller 649th payment of about $779.23, shortly before the 25-year amortization period ends. This is not an accelerated biweekly payment. These amounts illustrate the calculation method.
How to interpret the result and limits
The illustration holds the entered rate constant for the entire amortization. A mortgage commonly spans multiple contractual terms, and the rate, payment, and other terms may change at renewal.
The calculator does not model accelerated weekly or biweekly payments, extra regular payments, lump-sum prepayments, lender prepayment privileges or penalties, payment holidays, lender-specific dates or day-count conventions, or future renewal rates.
Twice-monthly, biweekly, and weekly payments are calculated from the monthly payment; they are not independently solved to end on exactly the same date. The schedule may therefore end slightly earlier and may have a smaller final payment.
The calculation assumes equally spaced payments made at the end of each payment period. Lenders may use different dates, contractual rules, and rounding practices, so a lender's payment amount, balance, or interest total may differ.
This is an educational estimate, not mortgage, borrowing, legal, tax, or other professional advice. It does not recommend a payment frequency or determine whether a mortgage is suitable or affordable.