About the Biweekly Mortgage Calculator
A biweekly mortgage plan replaces 12 monthly payments with a half-payment every two weeks. Because a year has 52 weeks, that adds up to 26 half-payments — the same as 13 monthly payments — so you quietly make one extra monthly payment every year. This calculator shows how much interest that extra payment saves and how much sooner the loan is paid off.
Enter your loan amount, rate and term. The calculator works out the regular monthly payment, the biweekly half-payment, and simulates both schedules to compare total interest and payoff time. It suits homeowners paid every other week who want to line mortgage payments up with paychecks, and anyone weighing a lender’s biweekly program.
The biweekly schedule assumes each half-payment is applied to the loan as soon as it is made, with interest charged per two-week period. Some servicers hold half-payments until a full payment builds up, which reduces the saving slightly; check how your lender applies them and whether any enrollment fee is charged.
With the default inputs, the interest saved is $88,121.78. Change any value above to recalculate instantly.
How to use the biweekly mortgage calculator
- 1Enter your loan amount or current balance.
- 2Enter the interest rate and the loan term.
- 3Compare the monthly payment with the biweekly half-payment.
- 4Read the interest saved and time saved to judge the benefit.
- 5Confirm with your servicer that half-payments are applied immediately and without fees.
Formula and method
M is the regular monthly principal-and-interest payment from the standard amortization formula. On the biweekly plan, half of M is paid every two weeks, 26 times a year, and interest is charged each period at the annual rate divided by 26. The simulation repeats the balance update until the loan reaches zero.
Twenty-six half-payments equal 13 monthly payments, so one extra payment goes straight to principal each year. Interest saved is total interest on the monthly schedule minus total interest on the biweekly schedule, and time saved converts the difference in payoff periods into months (26 periods = 12 months).
- M
- Monthly principal and interest payment
- r₂₆
- Biweekly rate = annual rate ÷ 26 ÷ 100
- Bₖ
- Loan balance after biweekly payment k
Worked examples
$300,000 at 6.5% for 30 years
The monthly payment is $1,896.20, so the biweekly payment is $948.10. Paying that every two weeks clears the loan in 628 payments — about 24 years and 2 months — and saves roughly $88,122 of interest compared with 30 years of monthly payments.
$200,000 at 5% for 15 years
On a 15-year $200,000 loan at 5% the half-payment is $790.80. The loan is gone after 347 biweekly payments (about 13 years 4 months), saving around $10,454 in interest — less than on a 30-year loan because there is less interest to cut.
$450,000 at 7% for 30 years
At 7%, a $450,000 loan costs $2,993.86 a month. Switching to biweekly half-payments ends it after 617 payments (around 23 years 9 months) and saves about $155,082 in interest.
Frequently asked questions
Does paying biweekly really save money?+
Yes, as long as each half-payment is applied to the loan. Twenty-six half-payments a year equal 13 monthly payments, and that extra payment goes to principal, cutting several years and tens of thousands of dollars of interest from a typical 30-year mortgage.
How many years does a biweekly mortgage save?+
On a 30-year loan at rates around 6–7%, biweekly payments usually shorten the payoff by roughly 5½ to 6½ years. Lower rates and shorter terms save less time; enter your own loan to see the exact figure.
Is biweekly the same as paying twice a month?+
No. Paying twice a month (semi-monthly) means 24 half-payments a year, which equals 12 monthly payments and saves almost nothing. Biweekly means every two weeks, 26 times a year.
Should I pay a fee for a biweekly program?+
Usually not. Some third-party programs charge setup or per-payment fees that eat into the savings. You can get the same effect for free by adding one-twelfth of a monthly payment as extra principal each month.
Can I make biweekly payments on any mortgage?+
Many servicers accept them, but some only apply full payments, holding half-payments in a suspense account. Ask your servicer how partial payments are credited before setting up a biweekly schedule.
Results are estimates for educational purposes and are not financial advice. Rates, fees and terms vary — confirm with your lender or a licensed advisor before making decisions.