Mortgage Payoff Calculator (2bi) Biweekly Payments Applied BiWeekly Who This Calculator is For: Borrowers who want to know when their loan will pay off, and how much interest they will save, if they use a biweekly payment plan, and if they make extra voluntary payments in addition to their required biweekly payment. What This Calculator Does:This calculator provides amortization schedules for biweekly payment mortgages, with or without additional payments, where the payments are applied biweekly.