Amortization Calculator
See your full loan breakdown — monthly payments, total interest, and payoff schedule.
Enter your loan details and click Calculate to see results.
What Is an Amortization Calculator?
An amortization calculator shows your monthly loan payment and a full breakdown of how each payment is split between principal and interest over the life of your loan. It works for any fixed-rate loan — mortgages, auto loans, personal loans, student loans, and more.
Results update instantly as you type, so you can experiment with different loan amounts, interest rates, or terms to find a payment that fits your budget.
How to Use This Calculator
Fill in each field to get your payment and amortization schedule. Here's what each input means:
Loan Amount
The total amount you are borrowing — before any down payment. For a mortgage, this is the home price minus your down payment. For an auto loan or personal loan, it's the total financed amount.
Annual Interest Rate
Enter the annual interest rate (APR) your lender has quoted. Even a small difference in rate has a major impact over time — a 0.5% higher rate on a $300,000 30-year mortgage adds roughly $31,000 in total interest.
Loan Term
The number of years (or months) you have to repay the loan. Common terms are 30 or 15 years for mortgages, 3–7 years for auto loans, and 1–7 years for personal loans. A shorter term means higher monthly payments but far less total interest paid.
Start Date (optional)
Set when your first payment begins to get accurate payment dates in your amortization schedule.
Extra Payments (optional)
Add a monthly, yearly, or one-time extra payment to see how it shortens your loan term and reduces total interest. Even an extra $100/month can save thousands — see the Extra Payments section below.
What Is Amortization?
Amortization is the process of paying off a loan through regular, equal payments made over a fixed period of time. Each payment you make covers two things:
- Interest — the cost of borrowing, calculated on your current remaining balance.
- Principal — the portion that directly reduces what you owe.
At the start of a loan, most of your payment goes toward interest because your balance is high. As you pay down the principal, the interest charged each month decreases — so more of each payment goes toward the principal. By the final payments, almost your entire payment is reducing the balance.
This structure applies to most consumer loans — mortgages, auto loans, personal loans, and student loans. Credit cards are revolving debt and work differently — they are not amortized the same way.
How Amortization Works
When you take out a loan, your lender calculates a fixed monthly payment that will pay off your full balance — principal plus interest — by the end of the loan term. The payment amount never changes, but what's inside each payment does.
Here's a real example across three key points in a loan's life:
| Payment | Monthly Payment | Goes to Interest | Goes to Principal | Remaining Balance |
|---|---|---|---|---|
| Month 1 | $1,688 | $1,000 | $688 | $199,312 |
| Month 90 (midpoint) | $1,688 | $651 | $1,037 | $129,467 |
| Month 180 (final) | $1,688 | $8 | $1,680 | $0 |
Example: $200,000 loan · 6% annual interest · 15-year term
Over the full 15 years, you'd pay $103,788 in total interest on top of the $200,000 principal — a total cost of $303,788. The calculator above shows this breakdown instantly for your own numbers.
The formula behind the calculation is:
M = P × [r(1+r)ⁿ] / [(1+r)ⁿ – 1]
- M = monthly payment
- P = loan amount (principal)
- r = monthly interest rate (annual rate ÷ 12)
- n = total number of payments (years × 12)
Amortization Schedule Explained
An amortization schedule — also called an amortization table — is a complete, payment-by-payment breakdown of your entire loan. For each payment period it shows:
- Payment number and date
- Total payment amount
- Interest portion of that payment
- Principal portion of that payment
- Remaining loan balance after that payment
The schedule is useful for more than just curiosity. You can use it to:
- See exactly how much of each payment reduces your balance vs. goes to your lender as profit.
- Find your exact remaining balance at any point — helpful when refinancing or selling a home.
- Understand why paying extra early in the loan saves the most money (interest is highest when the balance is highest).
- Plan ahead for tax purposes, since mortgage interest may be deductible.
This calculator generates a full monthly amortization schedule automatically. You can also view it as a yearly summary for a quicker big-picture view.
Extra Payments — Pay Off Your Loan Faster
Making extra payments reduces your principal faster. Since interest is calculated on your remaining balance, a lower balance means less interest every month going forward — which shortens your loan term and saves you money.
Three Ways to Add Extra Payments
- Extra monthly payment — a fixed additional amount added every month (e.g., $100 extra per month).
- Extra yearly payment — a lump sum once a year (e.g., putting your tax refund toward the loan).
- One-time payment — a single extra payment made at a specific point in the loan.
Here's how even modest extra payments impact a standard 30-year mortgage:
| Scenario | Monthly Payment | Total Interest | Loan Paid Off | Interest Saved |
|---|---|---|---|---|
| No extra payments | $1,199 | $231,676 | 30 years | — |
| +$100/month extra | $1,299 | $192,143 | ~26.5 years | $39,533 |
| +$200/month extra | $1,399 | $160,718 | ~23.5 years | $70,958 |
Example: $200,000 loan · 6% annual interest · 30-year term