Biweekly Mortgage Calculator
See how much interest and time you save by paying half your mortgage payment every two weeks instead of the full payment once a month.
A biweekly mortgage plan replaces one monthly payment with half a payment every two weeks. Because a year has 52 weeks, that adds up to 26 half-payments — the same as 13 monthly payments instead of 12. The extra payment goes straight to principal, so the loan is paid off years early and you pay less interest. This calculator shows exactly how much you save.
How to use this tool
- Enter the loan amount, or your current balance for an existing mortgage.
- Enter the interest rate.
- Choose the loan term (or the years left on it).
- Compare the interest, payoff time and yearly balances for both schedules.
Formula
Monthly payment M = P × r ÷ (1 − (1 + r)^−n)
Biweekly payment = M ÷ 2, paid 26 times a year at rate ÷ 26
P is the loan amount, r the monthly rate and n the number of months. The biweekly schedule is simulated payment by payment until the balance reaches zero.
Example
A $300,000 loan at 6.5% for 30 years has a monthly payment of $1,896.20. Paying $948.10 every two weeks instead clears it in 628 payments, about 24 years 2 months, and cuts total interest from $382,633 to $294,512, a saving of about $88,122.
Frequently asked questions
Is a biweekly plan worth paying a fee for?
Some servicers and third-party companies charge setup or per-payment fees. You get almost the same result for free by adding one-twelfth of a payment to each monthly payment, as long as your lender applies extra money to principal.
Does my lender apply half-payments right away?
Not always. Some programs hold the first half until the second arrives and apply a full payment once a month. The savings are then slightly smaller than shown here, but most of the benefit comes from the extra payment each year.
Is there a prepayment penalty?
Most US home loans today have none, but check your loan documents or ask your servicer before paying extra.
This tool gives an estimate for general information only. It is not financial, tax, legal or medical advice — check with a qualified professional before you rely on the result.
Last updated: 2026-10-30