How to use this calculator
- Enter the Loan amount (your current balance if the loan is already running).
- Enter the Interest rate and the Loan term in years.
- Read the Biweekly payment, Interest saved, Paid off in and Time saved.
- Compare the yearly chart of monthly and biweekly balances.
Why biweekly payments save money
A year has 52 weeks, so paying every two weeks means 26 half-payments, which equals 13 full monthly payments instead of 12. The extra payment goes straight to principal, which lowers the balance on which interest is charged for the rest of the loan.
Biweekly payment = M ÷ 2, with M = P · r(1 + r)^n / ((1 + r)^n − 1)- M = regular monthly payment
- P = loan amount
- r = monthly rate (annual rate ÷ 12 ÷ 100)
- n = number of monthly payments (years × 12)
- Extra paid per year = one monthly payment M
The calculator works out the standard monthly payment, then models the extra amount (one-twelfth of a payment each month), and compares how long the loan lasts and the interest paid.
Example: $300,000 at 6.5% for 30 years
The monthly payment is $1,896.20, so the biweekly payment is $948.10. Paying biweekly, the loan is finished in 290 months instead of 360, which is 70 months (almost 6 years) sooner, and you save about $87,256 in interest.
You pay an extra $1,896.20 each year, about $158 a month in effect. You are not paying more interest, you are paying principal faster.
The effect depends on the rate
At 4% on the same $300,000 over 30 years, the biweekly payment is $716.12 and the interest saved is about $33,398. The lower the rate, the less the extra payment saves, because less of each payment was interest to begin with.
The biggest benefit comes from starting early in the loan. Use the loan payoff calculator to test any other extra amount, such as a fixed $100 a month, and the amortization calculator to see the full schedule.
Check how your lender handles biweekly payments
This is the main risk. Some servicers hold the half-payment until the second one arrives and apply the whole to the monthly bill, which means you gain nothing. Others charge a setup or per-payment fee, sometimes through a third-party service.
Ask whether payments are applied when received, whether there is a fee, and whether the extra goes to principal. If not, you can get the same result free: divide your payment by 12 and add that to each monthly payment, or make one extra payment per year.
Ways to get more from it
- Start as early in the loan as you can; most of the saving comes from the first years.
- Make sure extra money is applied to principal and not held for the next payment.
- Weigh it against other uses of the money, such as high-interest debt or an emergency fund; see the mortgage calculator for the baseline.
- Keep an eye out for prepayment penalties in your loan terms.
Assumptions and limits
The calculator assumes a fixed rate, no prepayment penalty and that the extra amount is applied to principal in the month it is paid. Real biweekly programs may apply payments only at certain dates, so the saving can be slightly smaller.
Taxes, insurance and escrow are not included. Rely on your servicer's statements for exact amounts.
Frequently asked questions
Is a biweekly mortgage worth it?
It is if payments are applied to principal promptly and you are not charged a fee. The saving then depends mostly on the rate and how early in the loan you start.
Is biweekly the same as making one extra payment a year?
In effect, yes: 26 half-payments equal 13 monthly payments. You can reach the same result by adding one-twelfth of the payment to each month.
How much sooner will I pay off my mortgage?
On a 30-year, 6.5% loan, about 70 months. The exact time depends on rate and term, so use the calculator with your numbers.
Do I need my lender's permission for biweekly payments?
Often yes. Many servicers have a program for it, and some charge a fee. Alternatively, send extra principal yourself.