What is a biweekly mortgage payment?
With a biweekly plan you pay half of your normal monthly mortgage payment every two weeks instead of the full amount once a month. Because a year has 52 weeks, that works out to 26 half-payments — the equivalent of 13 full monthly payments rather than 12. The thirteenth payment goes entirely toward principal, and that is what shortens the loan. The biweekly rhythm itself is not magic; the savings come from the extra payment you quietly make each year.
Biweekly payments are popular with people who are paid every other Friday, because the mortgage lines up with paychecks and the extra payment happens automatically, without feeling like a sacrifice.
How the calculator works
First it computes your regular monthly payment with the standard formula:
Your biweekly payment is simply M ÷ 2. The calculator then offers two ways to model the payoff:
- Applied monthly (default). Most servicers and third-party biweekly programs collect your half-payments but only post a full payment to the loan once a month, then apply the accumulated extra. Over a year this is equivalent to paying M + M/12 every month, so that is how we model it.
- Interest accrues every two weeks. A few lenders offer true biweekly loans where each half-payment is credited immediately and interest is computed for each 14-day period at the annual rate ÷ 26:
balancek = balancek−1 − (M/2 − interestk)
The two methods give very similar results; true biweekly is marginally better because principal falls slightly sooner.
Worked example: $300,000 at 6.5% for 30 years
The regular monthly payment is $1,896.20, so the biweekly payment is $948.10. Over a year you pay $24,650.60 instead of $22,754.40 — an extra $1,896.20, exactly one monthly payment.
Applied the common way, that extra payment shortens the loan by about 70 months (5 years 10 months) and saves about $87,000 in interest compared with the $382,637 you would pay on the standard schedule. Not bad for a change that costs you about $158 a month.
Biweekly vs. adding 1/12 extra each month
Here is the secret the biweekly-program marketers do not advertise: you can get virtually the same result by adding one-twelfth of your payment to every monthly payment. In the example above, that is $158.02 extra per month. It requires no enrollment, no special program and no fees, and you can stop or change it anytime. Try it in our extra payment calculator and you will see a nearly identical payoff date.
Watch out for biweekly program fees
Some third-party companies charge a setup fee of several hundred dollars, plus a per-debit fee, to run a biweekly plan for you. They often hold your half-payments in their own account and forward them to your lender monthly. Fees eat directly into your savings, and holding your money adds risk. Before enrolling, ask your own servicer — many offer a free biweekly or "accelerated" payment option, or will accept extra principal online at no cost. If the only option has a fee, the do-it-yourself 1/12 method is almost always better.
Pros and cons of biweekly payments
- Pro — painless saving. Matching payments to a biweekly paycheck makes the extra payment almost invisible in your budget.
- Pro — big long-term impact. Five to seven years off a 30-year loan is typical at today's rates.
- Pro — faster equity. You build home equity faster, which can help you drop PMI sooner on a conventional loan.
- Con — less flexibility. Automatic drafts every two weeks can be tight in months with three paydays' worth of other bills.
- Con — possible fees. Third-party programs can charge enough to wipe out a meaningful share of the benefit.
- Con — opportunity cost. As with any prepayment, the money is locked in your house rather than an emergency fund or retirement account.
Does a higher rate make biweekly more valuable?
Yes. The higher your interest rate and the longer your remaining term, the more each extra principal dollar saves. At 3% the same strategy on a $300,000 loan saves far less interest than at 6.5% or 7%, though it still shortens the loan by several years. For a 15-year mortgage the dollar savings are smaller because there is less interest to cut in the first place.
Limitations
This calculator covers principal and interest only; escrow for taxes and insurance is excluded because it does not affect payoff speed. Results assume a fixed rate and on-time payments. Your servicer's exact crediting rules may differ slightly, which can change the payoff by a month or two.
Frequently asked questions
How much does a biweekly mortgage save?
On a $300,000, 30-year loan at 6.5%, biweekly payments save roughly $87,000 in interest and pay off the loan almost six years early. The exact amount depends on your balance, rate and remaining term.
Is biweekly the same as paying twice a month?
No. Twice a month is 24 half-payments a year, which equals 12 monthly payments and saves almost nothing. Biweekly means every two weeks, which is 26 half-payments.
Can I do biweekly payments myself?
Usually yes. Ask your servicer about a free biweekly option, or simply add one-twelfth of your monthly payment to each payment as extra principal for nearly identical results.
Are biweekly mortgage programs worth the fee?
Rarely. Setup and transaction fees reduce your savings, and the same benefit is available free by paying extra principal.
Does biweekly work on a 15-year mortgage?
Yes, it shortens a 15-year loan too, though the interest saved is smaller because a 15-year loan already carries less total interest.
Will biweekly payments help me remove PMI sooner?
Usually. Faster principal reduction gets you to 80% loan-to-value sooner, when you can request PMI removal on a conventional loan.
Sources
- Consumer Financial Protection Bureau: Mortgages
- Consumer Financial Protection Bureau: What is a prepayment penalty?
- Freddie Mac: Primary Mortgage Market Survey (PMMS), weekly average mortgage rates
Last reviewed: Oct 17, 2026. See how we calculate and test. Calculations use the standard fixed-rate amortization formula with interest rounded to the cent each period.