Mortgage Amortization Visualizer
See exactly how your mortgage balance falls over time, when your principal payment overtakes interest, and how extra payments accelerate your payoff date.
What is mortgage amortization?
Amortization is the process of systematically paying off a loan through regular, equal payments over a fixed period. With a mortgage, you make the same payment every month for the life of the loan. What changes month to month is the split between how much of that payment goes to interest and how much reduces your loan balance (principal). In the early years of a 30-year mortgage, the vast majority of each payment goes to interest. By the final years, almost every dollar goes to principal.
Why early payments are mostly interest
Interest on a mortgage is calculated as a percentage of your remaining balance. Because your balance is at its highest on day one, your first payment carries the highest possible interest charge. On a $400,000 loan at 7%, your monthly payment is $2,661. Of that first payment, approximately $2,333 goes to interest and only $328 goes to principal. By month 360, the ratio flips entirely -- nearly all of the payment is principal. This front-loading is not a trick by lenders; it is a mathematical result of how interest accrues on a declining balance.
The crossover point
Every amortizing mortgage has a crossover point -- the month when your principal payment first exceeds your interest payment. On a 30-year mortgage at 7%, this crossover happens around month 242, which is partway through year 21. At a lower rate of 4%, the crossover happens around month 153, which is partway through year 13. The higher the interest rate, the later in the loan the crossover occurs, and the more total interest you pay.
How extra payments work
Every extra dollar you pay toward your mortgage reduces your principal balance, which in turn reduces the interest that accrues in subsequent months. Because the loan term does not automatically shorten, each extra payment creates a compounding effect -- less future interest means more of your regular payment reaches principal, which accelerates the payoff further. On a $400,000 loan at 7%, paying an extra $300 per month brings the payoff forward by about 7 years and 9 months, to roughly 22 years and 3 months, and saves approximately $168,000 in total interest.
The timing of extra payments matters significantly. A $10,000 lump sum paid in year 1 saves far more than the same $10,000 paid in year 15, because the earlier payment prevents more compounding interest from accruing over a longer period.
How to use the amortization visualizer
Enter your loan amount, interest rate, and term. The visualizer generates your complete month-by-month amortization schedule and displays a balance curve showing how your loan falls over time. Use the extra payment field to see how additional monthly contributions or a one-time lump sum changes your payoff date and total interest. The annual payment chart shows the principal and interest breakdown for each year of the loan.
Frequently asked questions
What is mortgage amortization?
Amortization is the process of paying off your mortgage through regular monthly payments over the life of the loan. Each payment covers both interest and principal, but the split changes over time. Early payments are mostly interest -- on a 30-year loan at 7%, about 88% of your first payment goes to interest.
Why do I pay so much interest at the beginning of my mortgage?
Because interest is calculated on your remaining balance each month. At the start, your balance is highest, so the interest charge is highest. As you pay down the balance, each month's interest charge decreases slightly, allowing more of your fixed payment to reach principal.
When does my principal payment exceed my interest payment?
On a 30-year mortgage at 7%, the crossover point happens around month 242 (year 21). At a lower rate of 4%, the crossover happens around month 153 (year 12-13). Higher interest rates push the crossover later into the loan term.
How much does making one extra payment per year save?
Making one extra mortgage payment per year on a $400,000 30-year loan at 7% saves approximately $131,000 in total interest and cuts about 6 years off your loan term.
Does refinancing reset my amortization schedule?
Yes. When you refinance, you start a new loan with a new amortization schedule. If you have 22 years left on a 30-year loan and refinance into a new 30-year loan, you restart the interest-heavy early years of amortization. This is one reason why refinancing is not always financially beneficial even when rates drop.
Should I pay off my mortgage early or invest the extra money?
This depends on your mortgage rate versus your expected investment returns. If your mortgage rate is 7% and you believe you can earn more than 7% in investments, the math favors investing. If your mortgage rate is low (say 3-4%), early payoff may be less advantageous. Most financial planners suggest building a fully funded emergency fund and maxing tax-advantaged retirement accounts before making extra mortgage payments.
Calculations are estimates for educational purposes only and do not constitute financial advice. Consult a licensed mortgage professional before making any financing decision.