Amortization Schedule Calculator
See exactly how each mortgage payment splits between principal and interest over the life of your loan, and how extra payments can save you thousands.
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Amortization Schedule
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Frequently Asked Questions
What is an amortization schedule?
An amortization schedule is a table showing every monthly payment over the life of your loan, broken down into principal and interest. In the early years, most of your payment goes toward interest — on a $300,000 loan at 7%, your first payment of $1,996 puts $1,750 toward interest and only $246 toward principal. By year 15, the split is roughly even. By the final years, almost all of each payment reduces your balance. The schedule shows exactly when you’ll cross each milestone.
How do extra payments affect my mortgage?
Extra payments go directly toward principal, reducing both your balance and total interest. Adding $100/month to a $300,000 mortgage at 7% saves about $63,000 in interest and pays off the loan 4.5 years early. A single extra payment of $2,000 per year saves roughly $78,000 over the life of the loan. The earlier you make extra payments, the bigger the impact — an extra $200/month in year 1 saves far more than the same extra payment starting in year 15.
Why does so much of my payment go to interest at first?
Because interest is calculated on your remaining balance, and your balance is highest at the start. On a $300,000 loan at 7%, the lender charges 7% on roughly $300,000 in year one — that’s $21,000 in annual interest, or $1,750/month. As your balance drops, less interest accrues each month, and more of your fixed payment goes to principal. This “front-loading” of interest is why early extra payments have such a dramatic effect on total loan cost.
How much interest will I pay over the life of my mortgage?
On a 30-year fixed mortgage at 7%, you’ll pay roughly $1.39 for every $1 you borrow in total interest. A $300,000 loan costs about $418,527 in interest over 30 years, meaning you pay $718,527 total. A 15-year term at the same rate cuts total interest to about $185,586. Even at lower rates, the numbers are significant — a $300,000 loan at 5% still costs $279,767 in interest over 30 years. This is why shorter terms and extra payments make such a big financial difference.
What happens if I make biweekly mortgage payments?
Biweekly payments (half your monthly payment every two weeks) result in 26 half-payments per year, which equals 13 full monthly payments instead of 12. That one extra payment per year on a $300,000 mortgage at 7% pays off the loan about 4 years early and saves roughly $68,000 in interest. Some lenders offer biweekly payment programs, but they sometimes charge fees. You can get the same effect for free by dividing your monthly payment by 12 and adding that amount to each payment.
Can I see how a lump sum payment changes my payoff date?
Yes, use the calculator above to model lump sum scenarios. As a rough guide: a $10,000 lump payment in year 5 of a $300,000 mortgage at 7% shortens the loan by about 10 months and saves roughly $23,000 in interest. The same $10,000 applied in year 20 only saves about $7,000 because there’s less remaining interest to avoid. If you get a bonus, inheritance, or windfall, applying it to your mortgage early has the biggest payoff.