Biweekly Mortgage Calculator
See how paying half your mortgage every two weeks cuts the interest and shortens the term.
One extra payment a year
Twenty-six half-payments equal thirteen monthly payments, so you make one extra each year without feeling it.
Only if it is applied
The savings only happen if your lender credits the extra amount to principal, not just holds it.
What is a biweekly mortgage?
Half the payment, twice as often
A biweekly mortgage is not a different loan — it is a different payment schedule on the same loan. Instead of one monthly payment, you pay half of it every two weeks. Because there are 52 weeks in a year, that comes to 26 half-payments, which equal 13 full monthly payments rather than 12. According to consumer-finance resources such as the CFPB, that one extra payment a year goes straight to principal, so the balance falls faster and you pay interest for fewer years. This calculator shows your biweekly payment and the interest and time it saves against the standard monthly plan.
The biweekly payment is simply half the normal monthly payment; the magic is in the timing.
biweekly = monthly payment ÷ 2; 26 payments/year = 13 monthly paymentsA standard 30-year mortgage of 300,000 at 6.5% has a monthly payment near 1,896. Paid monthly, you make 12 payments a year for 30 years. Split it in half and pay 948 every two weeks, and you make the equivalent of 13 monthly payments a year — an extra one. Research shows that single extra annual payment, applied to principal, typically knocks several years off a 30-year term and saves a large amount of interest, because every dollar of principal paid early avoids all the future interest it would have accrued. The higher the rate and the longer the term, the bigger the effect.
The underlying calculation is the standard amortization formula, run twice: once on the monthly schedule and once on the accelerated biweekly one. According to Federal Reserve data on household mortgage debt, the largest cost in most home loans is the interest paid over time, so anything that shortens the repayment period has an outsized effect. Lender guidelines generally allow extra payments toward principal, which is exactly what a biweekly schedule does — it is the mechanism, not a special rate, that produces the saving.
You borrow 300,000 at 6.5% on a 30-year term.
Find the monthly payment
Amortizing 300,000 over 360 months at 6.5% gives about 1,896 a month.Halve it
The biweekly payment is 1,896 ÷ 2 = about 948 every two weeks.Count the payments
26 biweekly payments a year total 13 monthly payments — one more than the 12 you would otherwise make.See the result
That extra payment pays the loan off years early and saves tens of thousands in interest over the life of the loan.
Three things decide how much a biweekly schedule is worth on your loan.
The interest rate
Higher rates mean each early principal payment avoids more interest, so the savings grow with the rate.
The term length
Longer terms leave more interest to avoid, so a 30-year loan benefits far more than a 15-year one.
How early you start
The sooner you switch, the more of the loan's interest is still ahead of you to save.
If you want to compare other ways to get ahead, our construction loan calculator covers building a home, and our auto loan early payoff calculator shows the same accelerate-and-save idea on a car loan. The principle is identical: paying principal sooner buys you out of future interest.
The headline figure is your biweekly payment, half the monthly amount. The interest saved is the difference between the total interest on the monthly schedule and on the accelerated biweekly one, and the time saved is how many months earlier the loan is repaid. Together they show the trade: you commit a little more cash per year — the equivalent of one extra monthly payment — and in return you cut years off the loan and save a meaningful sum in interest. The same effect can be had by simply paying an extra one-twelfth of your payment each month, so the schedule is a commitment device as much as a math trick.
The math is exact; the real-world details matter.
Confirm the details with your lender
This estimate assumes every biweekly payment is applied to your balance on schedule and uses one rate for the whole term; it excludes taxes, insurance, PMI, and any fees a third-party biweekly program may charge. Some servicers hold biweekly payments and only apply them monthly, which erases the benefit, and a few charge enrollment fees that can outweigh the savings. This calculator is for informational and planning purposes only and is not financial advice. Confirm how payments are applied with your lender, and consider speaking with a qualified financial advisor before changing your payment plan.