Biweekly Mortgage Calculator

A biweekly mortgage payment is half your normal monthly payment, made every two weeks. Because there are 26 two-week periods in a year — not 24 — you end up making the equivalent of 13 full monthly payments per year instead of 12. That one extra payment per year goes entirely to principal, which shortens your loan term and cuts total interest paid.

On a $300,000 loan at 6.5% for 30 years, switching to biweekly payments typically saves around $50,000–$60,000 in interest and pays the loan off 5–6 years early. The exact amount depends on your loan balance, rate and remaining term — use this calculator to see your specific savings.

The calculator first derives your standard monthly payment using the level-payment amortization formula, then sets your biweekly payment to exactly half that amount. It simulates the repayment period by period at a biweekly interest rate (annual rate ÷ 26), counting how many periods it takes for the balance to reach zero, and compares that to the standard monthly schedule to show time saved and interest saved.

Yes, in the accelerated biweekly model used here. Your standard monthly payment is calculated first, then split in two. This is the widely understood 'biweekly mortgage' — you are not solving for a payment that amortizes over 26 periods per year at an equivalent rate, which would produce the same payoff date as monthly. The half-monthly-payment approach is what creates the acceleration benefit.

Not all lenders support a true biweekly program. Some hold both halves of a biweekly payment until month-end and then apply the full monthly payment — in which case there is no interest savings or term reduction. Ask your lender whether they credit each half-payment immediately to your balance. If not, you can replicate the effect by making one extra principal payment per year yourself.

Biweekly means every two weeks — 26 payments per year. Semimonthly means twice a month on fixed dates (e.g. the 1st and 15th) — exactly 24 payments per year. Semimonthly payments do not create an extra payment and therefore do not accelerate the payoff the same way biweekly payments do.

On a typical 30-year mortgage, biweekly payments cut roughly 4–6 years from the term. A 15-year mortgage loses about 1–2 years. The savings are larger at higher interest rates, because the extra annual payment has more interest-bearing balance to reduce.

Yes. The higher your rate, the more each day's outstanding balance costs you in interest, so attacking the principal sooner with an extra biweekly payment saves more. At very low rates (near 0%), the acceleration benefit approaches zero because there is little interest to save.

The math applies to any fully-amortising fixed-rate installment loan — car loans, personal loans, student loans — as long as your lender credits each biweekly half-payment immediately. Enter your loan balance, rate and remaining term and the calculator shows the same acceleration effect.

It is the difference between the total interest you would pay on a standard monthly schedule (monthly payment × total months − principal) and the total interest you actually pay on the biweekly schedule (sum of all biweekly interest charges until payoff). It does not include fees, taxes or insurance.

Yes, but the savings are proportionally smaller on a 15-year loan because there is less time for interest to compound and the loan is already on an aggressive repayment path. A 30-year loan benefits more because the extra payment makes a bigger dent in the remaining 30 years of interest.

The biweekly simulation counts the exact number of two-week periods until the balance hits zero, then divides by 26 to express it in years. Since the final period's payment often does not land exactly on a year boundary, you get a fractional year. Multiply the decimal by 12 to convert to months — for example, 24.15 years = 24 years and about 2 months.