Bi-Weekly Mortgage Payment Calculator
Calculate how much interest you save and how many years you cut from your mortgage by switching to bi-weekly payments. Perfect for homeowners wanting a simple, automatic way to pay off their home loan faster.
About this calculator
A bi-weekly mortgage strategy means paying half your monthly mortgage amount every two weeks. Because there are 52 weeks in a year, this results in 26 half-payments — equivalent to 13 full monthly payments instead of the standard 12. That one extra payment per year goes entirely to principal, compounding into significant savings over time. The calculator first computes your standard monthly payment using M = L × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where L is loan amount, r is the monthly rate, and n is total months. It then simulates a bi-weekly amortization loop using the bi-weekly rate (annual rate ÷ 26) and payment of M/2 plus any extra amount. The difference in total interest between the two schedules is the savings figure. Any additional bi-weekly extra payment accelerates payoff even further.
How to use
Take a $400,000 loan at 6.75% for 30 years. Monthly rate r = 6.75%/12 = 0.5625%; n = 360; M = 400,000 × [0.005625 × (1.005625)³⁶⁰] / [(1.005625)³⁶⁰ − 1] ≈ $2,594. Total interest on monthly schedule = ($2,594 × 360) − $400,000 = $533,840. Bi-weekly payment = $2,594 / 2 = $1,297 every two weeks. Simulating the bi-weekly amortization loop (using rate 6.75%/26 per period) shows payoff in roughly 308 bi-weekly payments (~23.7 years), saving approximately $56,000 in interest and 6.3 years.
Frequently asked questions
How much interest can I save by switching to bi-weekly mortgage payments on a 30-year loan?
The savings depend on your loan balance and interest rate, but bi-weekly payments typically save 20%–30% of total interest on a 30-year mortgage. On a $400,000 loan at 6.75%, the savings can exceed $50,000 and shave more than 6 years off the payoff date. Higher interest rates magnify the benefit because more of each payment is interest in early years. The savings come purely from that one extra annual payment reducing your principal balance, which then reduces the interest charged in every subsequent period.
What is the difference between bi-weekly mortgage payments and simply making one extra payment per year?
Mathematically, they produce nearly identical results since both strategies result in 13 monthly payment equivalents per year. The key difference is timing: bi-weekly payments apply principal reductions every two weeks, keeping your average daily balance slightly lower throughout the year and generating marginally more savings. Making a lump-sum extra payment once a year is simpler administratively but delivers the benefit all at once rather than spread through the year. If your lender charges a fee to set up bi-weekly drafting (some do), making a DIY extra payment annually or monthly is a cost-free alternative with nearly the same outcome.
Do all lenders allow bi-weekly mortgage payments, and are there any fees involved?
Most lenders accept bi-weekly payments, but the administration varies significantly. Some lenders natively support a bi-weekly draft program that applies funds immediately to your account; others hold the half-payment until a full payment accumulates, negating most of the benefit. Third-party bi-weekly payment services often charge setup fees of $200–$400 plus monthly fees, which can eat into your savings. The most reliable and free approach is to divide your monthly mortgage by 12 and add that amount as an extra principal payment each month, or simply make one full extra payment per year, achieving virtually the same payoff acceleration without any fees.