Biweekly Mortgage Calculator
Pay half your mortgage every 14 days instead of the whole thing once a month and you slip in a thirteenth payment each year. This tool amortizes both plans payment by payment so you can see the payoff dates, the interest saved, and exactly how much time disappears from your loan.
Loan details
How to use this calculator
1. Start with what you still owe
Enter your current principal balance rather than the original purchase price, then the rate on your note and the years left on the term. Those three numbers alone define the monthly payment the calculator uses as the baseline.
2. Set the first payment date
Biweekly schedules land on specific days, not tidy month boundaries, so the date matters. The calculator steps the biweekly plan forward 14 days at a time and the monthly plan one calendar month at a time to produce two real payoff dates.
3. Layer on extra principal
Use the extra field or the slider in the explore panel to stack additional principal on top. The amount is applied per monthly payment and split in half for each biweekly payment, so the comparison stays honest instead of quietly giving the biweekly plan more money.
4. Read the gap, not just the total
The balance chart shows both curves together. The biweekly line pulls away slowly at first and then drops steeply near the end, which is where most of the savings actually appear — the last years of a mortgage are almost pure principal.
About biweekly mortgage payments
How does a biweekly mortgage actually save money?
You pay half of your monthly payment every 14 days. Because a year holds 26 fourteen-day periods, you make the equivalent of 13 monthly payments instead of 12. That thirteenth payment goes straight to principal, and every dollar of principal retired early stops generating interest for the rest of the loan.
Does my lender have to accept biweekly payments?
Not every servicer applies half payments on the day they arrive. Some hold the money in suspense until a full monthly payment accumulates, which erases most of the benefit, and some charge a setup or per-payment fee for a formal biweekly program. Ask how partial payments are posted before you enroll.
Is biweekly better than just paying extra each month?
They are close cousins. Adding one twelfth of your payment to every monthly payment produces almost the same result as a biweekly schedule, and you keep full control with no fees. Biweekly wins slightly because principal drops two weeks sooner each cycle, and it suits people paid every two weeks.
How exact are these payoff dates?
This tool amortizes both plans period by period, using the annual rate divided by 12 for monthly and divided by 26 for biweekly. Real servicers may compute daily interest, round payments to the cent differently, or post payments on a business-day calendar, so treat the dates as a close planning estimate.