Amortization schedule
What is amortization schedule?
An amortization schedule is the month-by-month table showing how each payment splits between interest and principal, and what balance remains after every payment.
How it is calculated
Interest this month = remaining balance × (annual rate ÷ 12); principal = payment − interest
What it means in practice
Interest each month is the remaining balance times the monthly rate, so early payments are interest-heavy and the principal share grows over time.
This front-loading is why refinancing into a new 30-year term resets you to the interest-heavy part of the curve, even at a lower rate.
It is also why extra principal is so effective early: every dollar of principal removes all the future interest that dollar would have generated.