Why extra payments change the schedule
A normal amortization schedule applies each payment to accrued interest first and then to principal. When an additional amount is applied to principal, the remaining balance falls faster.
Because later interest is calculated from a smaller balance, the borrower may pay less total interest over the life of the loan. The exact change depends on when the extra payment is made, how much is paid, and how the lender applies it.
What to review after entering an extra payment
Confirm the payment date, the regular payment amount, and the additional principal amount. Then review the recalculated principal balance on the next several rows.
Also compare the revised payoff date and total interest with the original schedule. A correct recalculation should carry the lower balance forward rather than simply changing one isolated row.
Why row-by-row editing matters
Borrowers do not always make the same additional payment every month. Some make one large principal payment, while others add different amounts at irregular times.
The registered version of Amortization Pro lets you edit individual payment amounts and dates so that later rows can be recalculated from the actual payment history.
Model the schedule in Amortization Pro
Use the free online calculator for a straightforward schedule, or use the registered Windows software when individual payment rows must be edited, saved, retrieved, and recalculated.