The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. I'm looking for a Biweekly Loan Amortization Schedule that will allow me to input various additional payments depending on ability.Loan amortization schedule. 3. 4, Enter values, Loan summary. Biweekly payments accelerate your mortgage payoff. Payments, including the interest portion, in the amounts and dates specified in the above payment schedule.