Biweekly Mortgage Calculator

Enter your current balance, APR, remaining term and first payment date. Compare immediate biweekly crediting with standard monthly payments, an evenly spread DIY extra-principal plan, and a yearly 13th-payment strategy. Confirm your servicer’s posting rules before acting on the estimate.

Payoff acceleration workspace

Monthly vs. biweekly, with the posting assumption made explicit

Model half the regular principal-and-interest payment every 14 days, then compare it with two DIY ways to make the same annual extra principal.

Loan & plan

Mortgage balance APR (%) Years remaining Extra months First payment date Display currency

Optional extra principal & program fee

Extra principal each biweekly paymentBiweekly-plan fee per year

Fees reduce your financial benefit but do not change the amortization schedule.

Accelerated biweekly result—estimated interest saved

—•—

—

—Standard monthly P&I

—Every-14-days payment

—Extra paid per year vs monthly

—Average monthly cash outlay

—Interest saved less entered fees

—Entered fees through payoff

Four-way comparison

Same loan, different payment timing

Standard payoff: —

Strategy	Scheduled payment	Payoff	Total interest	Interest saved

“DIY monthly extra” spreads the same annual extra amount evenly across 12 months. “13th payment yearly” applies that annual extra once every 12 months. These comparisons help separate the value of paying extra principal from the value of payment timing.

Servicer reality check

Confirm these before enrolling in a biweekly plan

A calculator cannot tell when your servicer actually credits a half-payment. Mark what you have confirmed from your loan documents or servicer.

Accepts half-payments instead of holding themApplies extra amounts to principalNo fee that erodes the savingsNo relevant prepayment restriction0/4 servicer checks confirmed

Balance trajectory

Year-by-year remaining balance

Year	Standard	Biweekly	DIY monthly extra	13th payment

Actual 14-day model

Biweekly amortization schedule

#	Date	Payment	Principal	Interest	Balance

Method & limits

What this calculator assumes

The standard payment is fixed-rate principal and interest only.
The accelerated scenario pays half the standard monthly P&I every 14 days and uses a 26-period rate mathematically equivalent to monthly compounding.
Taxes, insurance, PMI and HOA charges are intentionally excluded because they do not reduce mortgage principal.
Some servicers hold partial payments until a full monthly payment is available; if yours does, the “13th payment yearly” comparison may be closer than immediate biweekly crediting.
Results are planning estimates, not a statement of your lender’s posting rules.

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Start with the broad calculator that matches the decision, then move to a specialist only when the loan structure, cash flow, tax treatment, debt strategy or savings goal genuinely changes.

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