Paying half your mortgage payment every two weeks adds up to 26 half-payments a year. That's 13 full monthly payments instead of 12. The extra one cuts principal, so a $400,000 loan at 7.03% ends 6 years and 3 months early.
That rate is Freddie Mac's 30-year average for the week of September 24, 2026. Here's where the extra payment comes from, and how to get it without a special program.
Where the 13th payment comes from
A year has 52 weeks, so paying every two weeks means 26 payments. Each one is half your monthly amount, which adds up to 13 monthly payments.
If you're paid every two weeks too, two months a year bring a third paycheck. That's the money that funds the extra payment.
Paying twice a month isn't the same thing. That's 24 half-payments, exactly 12 monthly payments, and no extra principal at all.
Savings are biggest on long, high-rate loans
The rates below are Freddie Mac survey averages for the week of September 24, 2026. The 6.30% row uses the 30-year average a year earlier.
| $400,000 loan | Monthly payment | Bi-weekly payment | Interest saved | Time saved |
|---|---|---|---|---|
| 30-year fixed at 7.03% | $2,669.27 | $1,334.64 | $137,847 | 6 yr 3 mo |
| 30-year fixed at 6.30% | $2,475.89 | $1,237.95 | $108,846 | 5 yr 8 mo |
| 15-year fixed at 6.42% | $3,466.86 | $1,733.43 | $30,316 | 1 yr 9 mo |
At 7.03%, the plan saves $137,847 of interest. At the year-earlier rate of 6.30%, it saves $108,846. On a 15-year loan, it trims only 1 year and 9 months, since principal already falls fast.
What the calculator assumes
The calculator halves your monthly principal and interest payment. It then models the plan as one-twelfth of a payment added to every monthly payment. That spreads the 13th payment evenly across the year.
Your real result depends on when your servicer credits each half-payment. Ask whether it's applied on receipt or held until a full payment has arrived. Taxes and insurance paid through escrow aren't in the bi-weekly figure either.
You can get the same result without a program
Since the plan works like one-twelfth extra each month, you can do that yourself. On the $400,000 loan at 7.03%, one-twelfth of $2,669.27 is $222.44:
| Paid monthly, plus | Monthly outlay | Paid off in | Total interest |
|---|---|---|---|
| $0.00 | $2,669.27 | 30 yr | $560,939 |
| $222.44 | $2,891.71 | 23 yr 9 mo | $423,092 |
| $500.00 | $3,169.27 | 19 yr 3 mo | $329,613 |
The $222.44 row pays off in 23 years and 9 months, just like the bi-weekly plan. It needs no enrollment, and you can skip it in a tight month. Add $500 instead, and the loan ends in 19 years and 3 months.
Before joining a lender's bi-weekly program, ask whether it charges a fee. The Consumer Financial Protection Bureau (CFPB) says prepayment penalties don't normally apply to small extra principal payments. It still suggests double-checking with your lender. The mortgage with extra payments calculator tests any other amount.
The trade-off: cash you can't easily get back
Each extra dollar avoids interest at your loan's rate, 7.03% in this example. In return, the plan moves one monthly payment a year, $2,669.27 here, from your bank account into home equity.
Prepaying doesn't normally lower the required payment, either. The calculator keeps it at $2,669.27 and shortens the term instead. If your income drops, next month's payment is still due in full. That's a reason to keep some savings on hand before you speed up the loan.
Extra principal can end PMI sooner
Paying private mortgage insurance (PMI)? The CFPB says you can ask to cancel it ahead of schedule. The trigger is extra payments that bring your balance to 80% of the home's original value. A bi-weekly plan gets you there sooner, because every 13th payment goes entirely to principal.
To see your full monthly cost, with property tax and insurance included, use the mortgage calculator.