Biweekly Mortgage Payoff Calculator
Compare regular monthly payments, half-payments every 14 days, and a monthly payment with extra principal. See payoff dates and estimated interest savings.
Payoff comparison
| Schedule | Regular payment | Payments | Payoff date | Total interest | Interest saved | Days earlier | Total paid |
|---|
Negative savings means higher interest under the modeled schedule. Savings include both payment timing and the different stated accrual conventions; they are not a universal lender result.
Payment-by-payment schedule
| Payment | Date | Amount | Interest | Principal | Remaining balance |
|---|
How the schedules differ
Standard monthly: a fixed principal-and-interest payment based on the balance, annual rate divided by 12, and remaining months. Interest is charged monthly on the outstanding balance. The final payment clears any remaining balance.
True biweekly: half of the calculated monthly payment is applied every 14 days, immediately after that interval's interest. Interest = opening balance × annual rate × 14 / 365. This is simple interest between payments, using a fixed 365-day denominator even in leap years. It is not twice-monthly payments and does not model a servicer holding partial payments.
Monthly plus equivalent extra: the normal payment plus one-twelfth of that payment as additional principal every month. Twenty-six half-payments over 364 days equal approximately 13 monthly payments, so this extra monthly amount approximates the same annual budget. Calendar years can contain 26 or 27 biweekly dates; dates and cent rounding mean the budgets are not identical.
Regular monthly payment is rounded up to a cent; the half-payment and monthly extra are rounded to the nearest cent. Interest is rounded to cents per payment period. All schedules reduce the final payment to the amount owed. Monthly dates keep the original day of month and clamp to month end when necessary. Biweekly dates advance exactly 14 days, without business-day adjustments.
Fixed-rate, fully amortizing principal-and-interest loans only. No escrow, insurance, taxes, late fees, enrollment fees, prepayment penalties, unpaid starting interest or changing rates are modeled. The two interest conventions are deliberately explicit: actual servicer results can differ. Verify your loan's accrual basis, payment application and extra-principal instructions.
Source: CFPB guidance on partial mortgage payments. Reviewed October 5, 2026.