Mortgage Calculator with Extra Payments
Start with the regular monthly payment, then compare extra principal, payoff date, total interest, affordability, and what a biweekly plan may save over time.
Enter your loan numbers
Monthly and biweekly payoff comparison
How much house can I afford?
Use this before shopping for a home. It estimates the full monthly housing payment and checks it against income and other monthly debt.
How the math works
The standard monthly plan uses the mortgage payment formula for principal and interest. The biweekly estimate uses half of the standard monthly principal and interest payment every 2 weeks, which equals 26 half-payments per year. That creates the effect of 13 full payments per year.
Extra monthly principal is added to both plans so the comparison stays fair. Taxes and insurance are shown in the payment estimate, but they do not reduce mortgage principal.
APR is converted into a monthly rate for the amortization estimate. The calculator shows estimated interest and principal movement, but your exact lender statement may differ because of daily interest rules, escrow changes, fees, or how the servicer applies partial payments.
The affordability estimate uses gross monthly income for the debt to income check. It is a planning estimate, not a loan approval. A lender may count income, credit, debts, insurance, taxes, PMI, and loan program rules differently.
Important before you switch to biweekly payments
Ask your mortgage servicer how partial payments and extra principal are applied. Some lenders apply extra principal right away. Others may hold partial payments until a full payment is available. Avoid paid third-party biweekly programs unless you fully understand the fee and can confirm the extra money goes to principal.