How extra payments change a mortgage payoff

The scheduled payment stays the same

The payoff calculator uses the same monthly mortgage schedule as the mortgage calculator. Interest for a month is the unpaid balance times the annual rate you enter, divided by 12. The scheduled principal is the payment minus that interest.

Extra principal is applied after the scheduled principal. It cannot be larger than the balance that remains. The last payment clears whatever is left. The rate does not change during the term.

What moves the payoff date

A monthly extra starts with the first payment and continues until the balance is gone. An annual extra is added once each year in the month you choose. A one-time extra is applied only in the month and year you enter. If that month is before the first payment, the schedule does not apply it.

The original payoff is the same loan with the monthly, annual, and one-time extras set to zero. The page reports how many months separate the two dates and how much interest the extra principal avoids in this model.

What this payoff leaves out

Taxes, homeowners insurance, mortgage insurance, and closing costs are not part of this schedule. Payments are monthly. Biweekly drafts and adjustable rates are not calculated here.

Paying extra principal can reduce interest in this model. It does not mean a lender will accept the payment or report the same payoff date. A servicer can apply extra principal on a different day.

Needs review before launch. A servicer can apply extra principal on a different day or limit a payment that is larger than the balance.

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Related guides

• How mortgage payments are calculated
• How this refinance comparison works
• What affects monthly mortgage costs?

Read the methodology

Written to explain how this site’s calculators work. Not a review by a licensed mortgage professional, and not a recommendation to borrow. These notes are not financial, tax, or legal advice.