Home / Amortization Calculator
Amortization Calculator
How much of each payment goes to interest, and how much pays the loan down? This amortization calculator shows the monthly payment, the total interest, and the full schedule — year by year and month by month.
Year by year
Principal and interest paid each year, and the balance left at the end of the year.
| Year | Principal paid | Interest paid | Balance |
|---|
First 12 months
The first year, month by month. Early payments are mostly interest.
| Month | Payment | Principal | Interest | Balance |
|---|
How to use this calculator
- Enter the loan amount, the interest rate and the term.
- The calculator shows the monthly payment and the total interest.
- Read the year-by-year table to see the balance fall and the interest share shrink.
- Check the first 12 months to see how little principal an early payment covers.
Formula and method
Each month, interest = balance × annual rate / 12. The rest of the fixed monthly payment goes to principal, and the balance falls by that amount. The payment itself comes from the standard formula: M = P × r × (1+r)n / ((1+r)n − 1). Early on, the balance is large, so most of the payment is interest. Late in the loan, the balance is small, so most of the payment is principal.
Worked example
$320,000 loan, 6.5% example rate, 30 years: the monthly payment is $2,022.62. In month 1, interest is $1,733.33 and principal is only $289.28, leaving a balance of $319,710.72. By month 12, interest is $1,715.62 and principal is $307.00, with a balance of $316,423.28. In the first year you pay $3,576.71 of principal and $20,694.68 of interest. In the last year, year 30, it flips: principal is $23,438.01 and interest is only $833.39. The last payment, month 360, is $2,011.72 of principal and $10.90 of interest, and the balance reaches $0.00. Total interest over the loan is $408,142.36, and total paid is $728,142.36.
Frequently asked questions
What is an amortization schedule?
A list of every payment on a loan, showing how much of each payment is interest, how much is principal, and the balance left after it. This page builds one for any loan amount, rate and term.
Why is the first payment mostly interest?
Interest is charged on the balance, and the balance is at its largest at the start. On the $320,000 example, month 1 is $1,733.33 of interest and only $289.28 of principal. As the balance falls, the interest share falls with it.
How much interest will I pay on a $320,000 mortgage?
At a 6.5% example rate over 30 years, total interest is $408,142.36 — more than the loan itself. A shorter term or extra payments cut that figure a lot; try the extra payment calculator to see by how much.
Does the monthly payment change over the loan?
No, on a fixed-rate loan the payment stays the same every month. What changes is the split: interest falls and principal rises until the loan is paid off.
What is the difference between amortization and a mortgage calculator?
A mortgage calculator gives you the monthly payment. An amortization calculator shows the payment plus the full schedule behind it — every month, every dollar of principal and interest.
Sources and method. Standard amortization formula: monthly rate r = annual rate / 12, n = years × 12, payment M = P × r × (1+r)n / ((1+r)n − 1). PMI usually ends when the loan balance reaches 80% of the home value (Consumer Financial Protection Bureau guidance). Affordability uses the 28/36 rule of thumb used by many lenders. Rates in examples are examples only, not live market rates. Results are estimates, not financial advice.
Estimate, not financial advice. This calculator uses the standard amortization formula and the numbers you type in. It is not a loan offer and not financial advice. A lender will check your credit, income and debts and quote its own rate and fees before you borrow.