Biweekly Mortgage Calculator
Compare standard monthly mortgage payments with a biweekly schedule. See your estimated interest savings, how many years earlier you could pay off your loan, and the impact of adding optional extra principal to each biweekly payment.
Enter your mortgage details
Enter your loan amount, interest rate, and term. Choose a quick preset or enter your own values, then click Calculate.
Why biweekly works
26 biweekly payments = 13 monthly-equivalent payments per year instead of 12. That one extra payment per year goes entirely toward principal — compressing the loan and reducing the interest base for every future period.
Extra principal tip
Even $50–$100 extra per biweekly payment can save tens of thousands in interest on a 30-year mortgage. Use the extra principal field to model different scenarios before committing.
How biweekly mortgage payments work
A biweekly mortgage payment schedule means you make a payment every two weeks instead of once a month. Because there are 52 weeks in a year, this produces 26 half-payments — or the equivalent of 13 full monthly payments per year instead of the standard 12.
That extra payment applies directly to principal, which reduces the outstanding balance faster. A smaller balance means less interest accrues in each subsequent period — creating a compounding acceleration effect that grows more significant over the life of the loan.
Mortgage formulas used
Biweekly vs semi-monthly — not the same
These two are frequently confused. Semi-monthly means 24 payments per year (twice a month on fixed dates). Biweekly means 26 payments per year (every two weeks). The extra 2 payments per year in a biweekly schedule are what create the acceleration effect — semi-monthly does not achieve this.
Frequently asked questions
What is a biweekly mortgage payment?
A payment made every two weeks instead of once a month. In a full year this produces 26 half-payments — equivalent to 13 full monthly payments. The extra payment reduces principal faster than a standard monthly schedule.
Does biweekly always save interest?
Yes, mathematically — as long as the lender applies each payment when received rather than holding it until month-end. If the servicer batches biweekly payments and only credits monthly, there is no acceleration benefit. Always confirm the payment application policy with your lender.
Can I get the same benefit without a biweekly programme?
Yes. Simply make one extra full monthly payment per year, or divide your monthly payment by 12 and add that amount to every monthly payment. This replicates the equivalent-of-13-payments effect without enrolling in a lender programme or paying any programme fees.
How much can I save on a typical 30-year mortgage?
On a $300,000 mortgage at 6.5% over 30 years, switching to biweekly payments can save approximately $50,000–$60,000 in total interest and reduce the payoff time by 4–5 years. The exact figure depends on when payments are applied and whether any extra principal is included.
Does adding extra principal help more than just going biweekly?
Both strategies reduce principal faster and save interest. They also stack — biweekly payments plus extra principal per payment produces the largest savings. Use the extra principal field in this calculator to model the combined effect.
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Disclaimer
This biweekly mortgage calculator provides estimates based on standard amortisation formulas with simplified biweekly simulation. Results do not account for escrow, taxes, insurance, lender fees, variable rates, or servicer-specific payment application policies. Always verify results with your mortgage servicer before making financial decisions.