Mortgage Payment Calculator (7d) Mortgage Payments With Temporary Buydowns Who This Calculator is For: Borrowers who want an amortization schedule that shows the lower monthly payments in the early years from setting up a buydown account, and the amount that must be deposited in the account. What This Calculator Does: The calculator displays the amortization schedule, including withdrawals from the buydown account, and the amount that must be deposited in the buydown account with and without interest.