Biweekly Mortgage Payment Calculator

Quick answer: On a $300,000 loan at 6.5% over 30 years, roughly $75,000 in interest and about 5 years off the loan — because 26 half-payments equal 13 full monthly payments a year instead of 12.

How biweekly payments pay off a mortgage early

26 half-payments a year = 13 full monthly payments, not 12

A monthly mortgage is 12 payments a year. Pay half that amount every two weeks and — because a year has 26 two-week periods — you make 26 half-payments, equal to 13 full payments. That one extra payment a year goes straight to principal, and the compounding works in your favour for the rest of the loan.

On a $300,000 loan at 6.5% over 30 years, the standard plan costs about $383,000 in interest. Biweekly cuts the loan to roughly 24–25 years and saves on the order of $75,000 in interest — from the same money, just paid on a different rhythm.

The catch nobody mentions

• Your servicer must apply the extra to principal. Some hold your half-payments and only apply them monthly, saving you nothing. Confirm in writing before starting.
• "Biweekly plan" fees are a scam. Companies charge $300–500 to "set up" biweekly payments. You can do exactly the same thing free — just pay 1/12 extra principal each month, or make one extra full payment a year. Same result, zero fee.
• Prepayment penalties. Rare on US mortgages, but check your note.

The DIY version (identical savings, no plan needed)

Divide your monthly payment by 12 and add that to each monthly payment as extra principal. That replicates the biweekly effect without changing your billing. Model any extra-payment amount with the loan payoff calculator, or see the full schedule on the amortization calculator.