Amortization Calculator
See exactly where every dollar of your loan payment goes — a detailed breakdown of principal and interest over the life of your loan.
Amortization Calculator
See how your loan payments break down between principal and interest over time.
Loan Payoff Details
In years:
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The Anatomy of a Mortgage Payment
Slide through all 360 payments of a $300K loan at 6.5% and watch the principal-interest split change in real time.
Payment Number
In Year 1, roughly goes to the bank as interest. Extra payments now have the biggest impact on your total cost. You are through your loan, but you have already paid the majority of the total interest. Every extra dollar now accelerates your payoff. Past the halfway mark, most of your payment builds equity. Your remaining balance of is shrinking fast. Almost there. Only remains and nearly every dollar goes straight to principal.
Reading the Amortization Schedule
Four key columns tell the full story of your loan.
Payment Number
Each row in the schedule represents one monthly payment. A standard 30-year mortgage has 360 payments. A 15-year has 180. This column lets you track exactly where you are in the journey.
Tip: Bookmark your current payment number and check quarterly to see your progress accelerate as more goes to principal.
Principal Portion
This is the amount reducing your actual loan balance each month. It starts small and grows larger with every payment as less interest accrues on the shrinking balance. Any extra payments you make go entirely to principal.
Example: On a $300K loan at 6.5%, payment #1 sends only $271 to principal. By payment #180 (year 15), that jumps to $770.
Interest Portion
This is what you pay the lender for the privilege of borrowing. Calculated as your remaining balance multiplied by the monthly interest rate. It starts high — dominating early payments — and decreases steadily as your balance falls.
Reality check: On a $300K / 6.5% / 30-year loan, you pay roughly $382,000 in total interest — more than the loan itself.
Remaining Balance
Your outstanding loan amount after each payment. Watching this number decrease is motivating and helps you set intermediate milestones. The curve is not linear — it decreases slowly at first, then accelerates dramatically in later years.
Milestones to celebrate: Dropping below $250K, hitting 20% equity (PMI elimination), reaching the halfway point, and watching the final $50K evaporate.
Using Amortization to Your Advantage
Three strategies that turn amortization knowledge into real savings.
Make Extra Payments Early
Front-loaded interest means early dollars have outsized impact
Because interest is calculated on the remaining balance, extra payments in the first few years have an outsized impact. A $200 extra payment in month 1 saves far more than the same payment in month 200 because it reduces the balance that interest compounds on for decades.
The numbers: On a $300K / 6.5% / 30-year loan, adding just $200/month from day one saves over $96,000 in interest and cuts 7 years off the loan.
Time Your Refinancing
Refinancing resets the amortization clock — know when it helps
If you are past the midpoint of your loan, most of your payment already goes to principal. Refinancing resets the amortization schedule, potentially increasing your total interest paid even at a lower rate. Use your amortization schedule to calculate whether the rate drop justifies the reset.
Rule of thumb: Refinancing makes the most sense in the first third of your loan when you are paying the most interest. After year 20 of a 30-year loan, the math rarely favors a refinance.
Set Milestones
Break the long journey into achievable targets
Rather than focusing on the full payoff (which can feel overwhelming), use the amortization schedule to set intermediate targets. Each milestone provides motivation and a sense of progress on the journey to being debt-free.
Key milestones: 20% equity (eliminate PMI and save $100-$300/month), 50% equity (you own more than you owe), under $100K remaining (the finish line is in sight), and final payoff.
Frequently Asked Questions
Amortization is the process of paying off a loan through regular, scheduled payments over time. Each payment is split between principal (reducing the loan balance) and interest (the cost of borrowing). The schedule shows exactly how much of each payment goes where.
Interest is calculated on the remaining balance. When your balance is high, more interest accrues. As you pay down principal, the interest portion shrinks and the principal portion grows. This is why extra payments early in the loan are especially powerful.
Extra payments go directly to principal, which reduces the balance that future interest is calculated on. This shifts the entire remaining schedule, allocating more of each future payment to principal and less to interest. Even small extra payments compound significantly over time.
The mortgage calculator focuses on the big picture — total interest saved, payoff timeline, and the impact of extra payments. The amortization calculator provides a detailed month-by-month breakdown showing exactly how each payment is allocated between principal and interest.
Yes. Amortization applies to any installment loan: car loans, student loans, personal loans, and home equity loans. Enter the loan amount, interest rate, and term to see the full payment schedule for any fixed-rate loan.
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