How biweekly mortgage payments work
With a biweekly payment plan you pay half of your normal monthly mortgage payment every two weeks. Because a year has 52 weeks, that's 26 half-payments, the equivalent of 13 monthly payments a year instead of 12.
That 13th payment goes straight to principal. Over the life of a loan, the extra principal snowballs: each payment reduces the balance that future interest is charged on, so more of every later payment goes to principal too.
What the calculator shows
- Payoff time: how long the loan lasts with payments every two weeks, compared with your current monthly schedule.
- Interest saved: total remaining interest on the monthly schedule minus total interest on the biweekly schedule.
- Program fees: if a lender or third-party company charges for a biweekly program, enter the fees under Program fees to see your net saving.
- The free alternative: adding one-twelfth of your payment to each monthly payment as extra principal. It costs nothing to set up and gives almost the same result.
How it's calculated
Biweekly payment = M ÷ 2, paid 26 times a year
Interest per two-week period = balance × rate ÷ 26
The calculator runs the loan down period by period until the balance reaches zero. It assumes each half-payment is applied to your loan when you make it. If your servicer holds half-payments until a full monthly payment arrives, your saving will be slightly smaller, but you'll still get the benefit of the extra annual payment.
Worked example
A $300,000, 30-year mortgage at 6.5% has a monthly payment of about $1,896 and costs about $382,600 in interest over its life.
- Biweekly: pay $948.10 every two weeks and the loan is gone in about 24 years and 2 months, nearly 6 years early, saving about $88,100 in interest.
- With a paid program charging a $395 setup fee and $2.50 per payment, about $1,970 in fees over the life of the loan, the net saving falls to about $86,200.
- DIY: paying $2,054 a month (your payment plus 1/12) pays the loan off in 24 years and 2 months too, with about $295,400 in total interest, practically the same result with no fees and no change to your payment schedule.
Is a biweekly mortgage worth it?
The extra payment is the reason it works, not the calendar. So the real question is whether you can comfortably afford roughly 8% more toward your mortgage each year. If you can, it's a simple, low-risk way to build equity and save interest. Before you start:
- Avoid fees where you can. A free extra-principal payment usually beats a paid program.
- Check for prepayment penalties. Most US mortgages don't have them, but confirm with your lender.
- Cover the basics first. An emergency fund, any employer retirement match and high-interest debt usually come before mortgage prepayment.
- Align with your paycheck. If you're paid every two weeks, a biweekly schedule can make budgeting easier, because two months a year you'll get a "third" paycheck that covers the extra half-payment.
Frequently asked questions
How much does a biweekly mortgage save?
On a typical 30-year loan, paying half the monthly payment every two weeks pays the loan off roughly 4 to 6 years early, depending on your rate. The higher the rate and the earlier you are in the loan, the bigger the saving. Enter your own numbers above to see your figure.
Why does paying every two weeks make a difference?
There are 52 weeks in a year, so paying every two weeks means 26 half-payments, the same as 13 full monthly payments instead of 12. That extra payment goes entirely to principal. Paying slightly earlier also reduces the balance interest is charged on, but the extra payment is the main effect.
Do I need to sign up for a biweekly program?
No. Some lenders and third-party companies charge setup or per-payment fees for biweekly programs, and some simply hold your half-payment until the full monthly amount arrives. You can get almost the same result for free by adding one-twelfth of your payment to each monthly payment as extra principal. The calculator shows that option too.
Will my lender apply biweekly payments correctly?
Ask before you start. You want extra money applied to principal, not held in a suspense account or applied to next month's payment. Check your statements after the first few payments to confirm your principal balance is falling faster.
Is it better to pay biweekly or invest the extra money?
It depends on your mortgage rate, your other debts and your goals. Paying down a mortgage gives a guaranteed return equal to your interest rate. Investing may earn more over time but with risk. Many people first pay off higher-interest debt and build an emergency fund.
Sources
- What is a prepayment penalty?, Consumer Financial Protection Bureau
This calculator is for educational purposes and gives estimates based on the numbers you enter. It is not financial, tax or legal advice. Last reviewed October 2026.