Biweekly Mortgage Payoff Calculator
Paying half your mortgage every 2 weeks means one extra full payment per year. Calculate how much time and interest you save vs the standard monthly schedule.
How Biweekly Mortgage Payments Work
A biweekly mortgage schedule splits your normal monthly payment in half and charges that amount every 14 days. Because a year has 52 weeks, you end up making 26 half-payments — the equivalent of 13 monthly payments instead of 12. That single extra payment each year is applied directly to principal and compounds over the life of the loan, knocking roughly 5 to 7 years off a 30-year mortgage and saving tens of thousands in interest. You do not need to refinance to do this.
This calculator amortizes both schedules — standard monthly and true biweekly — using the same interest rate and principal, then shows you exactly how many years you save and the total lifetime interest difference.
Biweekly vs Monthly Amortization
The math is straightforward. Under a monthly schedule, interest accrues on the current balance each month, and the fixed payment covers that interest plus a bit of principal. Under a true biweekly schedule, interest accrues for only 14 days before each half-payment, and the extra 13th annual payment attacks principal directly. Early in the loan — when 70 to 80 percent of your monthly payment goes to interest — this small principal boost saves a disproportionate amount over the remaining term.
Fake biweekly programs run by some servicers charge a fee and just hold your half-payment until month-end, giving you no benefit. A true biweekly either applies the payment immediately or you DIY by sending one extra full payment per year labeled "apply to principal only" — same math, zero fees.
When Biweekly Payments Make Sense
Biweekly is ideal if your paycheck is biweekly and you already have an emergency fund, no high-interest debt, and a mortgage rate above 4.5%. The higher your rate, the bigger the savings. On a $350,000 loan at 6.5% on a 30-year term, biweekly saves roughly $80,000 in interest and pays the loan off about 5.5 years early — a 20% acceleration with zero lifestyle change.
Skip biweekly if your rate is under 4% (the opportunity cost versus investing in index funds is higher than the interest saved), if you have credit card debt over 10% APR, or if your lender does not apply partial payments immediately — check the servicer's policy before switching. You can also combine biweekly with a small extra amount each payment to accelerate even further. Last updated April 2026.