A payoff letter provides instructions on how to pay off a loan with a lump sum before the loan term ends. Learn how payoff letters work.I'm selling my house with a closing date of January 9th. I received my mortgage payoff letter from Pennymac that is good through January 12th. In this video I provide a clear guide on how to create a loan amortization schedule in Google Sheets and Microsoft Excel. Make math easier with these free calculator templates. The tutorial shows how to build an amortization schedule in Excel to detail periodic payments on an amortizing loan or mortgage. Enter your mortgage details here. Enter extra payment amount in relevant month rows. Use this calculator to see how making extra payments affects how soon you can pay off your mortgage and how much interest you pay on your home loan.