Amortization Schedule

Quick Definition

An amortization schedule is a payment-by-payment table that shows how a loan is repaid over its full term. Each row displays one payment period and breaks it into two components: the portion that pays interest to the lender and the portion that reduces the outstanding loan balance (principal). The schedule also shows the remaining balance after each payment, tracking the loan from full balance to zero.

What It Means

When you take out a loan, the lender does not simply divide the balance by the number of payments. Interest accrues each month on the remaining balance. In early payments, most of your money goes to interest. As the balance shrinks over time, the interest portion shrinks and the principal portion grows. This gradual shift is called amortization.

Understanding your amortization schedule is one of the most valuable things a borrower can do. It shows you:

• Exactly how much total interest you will pay over the loan's lifetime
• How extra payments dramatically cut interest costs
• Why paying off a 30-year mortgage early saves tens of thousands of dollars

How It Works

The Math Behind Each Payment

For a fixed-rate loan, the monthly payment is calculated using this formula:

M = P x [r(1+r)^n] / [(1+r)^n - 1]

Where:

• M = Monthly payment
• P = Loan principal (amount borrowed)
• r = Monthly interest rate (annual rate / 12)
• n = Total number of payments (years x 12)

Then for each period:

• Interest portion = Remaining balance x monthly interest rate
• Principal portion = Monthly payment - interest portion
• New balance = Previous balance - principal portion

Reading an Amortization Schedule: Full Example

Loan details: $300,000 mortgage at 6.5% interest, 30-year term

Monthly payment: $1,896

Total paid over 30 years: $682,560 Total interest paid: $382,560 Total principal: $300,000

You pay $382,560 in interest on a $300,000 loan. That is 1.28 times the original loan amount, paid purely in interest.

As of July 2026, the average 30-year fixed mortgage rate was approximately 6.58% according to Freddie Mac's Primary Mortgage Market Survey. The 15-year fixed rate was around 6.10%. Rates have fluctuated between 6.4% and 6.8% through the first half of 2026.

The Front-Loaded Interest Effect

The table below shows how the principal/interest split changes over time on the same $300,000 loan at 6.5%:

The crossover point where more of your payment goes to principal than interest happens around year 19 on a 30-year loan at 6.5%. At higher rates, the crossover comes later. At lower rates, it comes earlier.

Why This Matters: The Power of Extra Payments

Extra principal payments early in a loan have an outsized impact because they eliminate future interest that would have compounded on that balance.

$300,000 mortgage at 6.5%, 30-year term. What happens with extra payments?

Adding just $200 per month saves nearly $100,000 in interest and pays off the loan more than 7 years early. You can model your own scenario with our mortgage payoff early calculator.

Amortization Schedule for Different Loan Types

15-Year vs. 30-Year Mortgage Comparison

Same $300,000 loan at 6.5%:

The 15-year mortgage costs $718 more per month but saves $212,040 in total interest. For borrowers who can afford the higher payment, the math strongly favors the shorter term. Use our house affordability calculator to see what loan size fits your budget.

ARM Loans and the Amortization Schedule

Adjustable-rate mortgages (ARMs) have amortization schedules too, but the schedule resets when the interest rate adjusts. A 5/1 ARM is fixed for 5 years, then adjusts annually. Each rate adjustment creates a new amortization calculation based on the current remaining balance and new rate.

This is why ARMs introduce uncertainty: the schedule you receive at closing only applies to the fixed period. If rates rise, your payment increases and more of it goes to interest, slowing balance reduction.

How to Get Your Amortization Schedule

1. Ask your lender: Lenders are required to provide amortization information. Request a complete schedule at closing.
2. Use an online calculator: The Consumer Financial Protection Bureau offers a free mortgage calculator, and sites like Bankrate and NerdWallet provide amortization tools.
3. Build your own in a spreadsheet: Using the formulas above, you can recreate your exact schedule in Excel or Google Sheets.
4. Check your mortgage statement: Most monthly statements show current balance, interest paid, and principal paid. These match your schedule.

Key Points to Remember

• Early loan payments are mostly interest: on a 30-year mortgage at 6.5%, over 85% of your first payment is interest
• Total interest over a 30-year mortgage can exceed the original loan amount at rates above 5%
• Extra principal payments early in the loan create disproportionately large savings in total interest
• The 15-year mortgage costs more monthly but saves six figures in interest compared to a 30-year
• ARM loans have amortization schedules that reset each time the interest rate adjusts
• Your amortization schedule is a fixed document for fixed-rate loans: your payment never changes

Common Mistakes to Avoid

• Ignoring the amortization schedule at closing: Many borrowers sign without reviewing how slowly their balance declines in the first 5 years. On a $300,000 loan at 6.5%, only about $19,000 of principal is paid down in the first 5 years, while $91,000 goes to interest.
• Refinancing into a new 30-year loan repeatedly: Each refinance restarts the front-loaded interest phase. A borrower who refinances every 7 years into a new 30-year loan never escapes the high-interest phase and pays far more total interest than someone who holds a single 30-year loan to term.
• Assuming biweekly payments save money because of frequency: Biweekly payments save money because they result in 13 monthly payments per year, not because of any magic in the timing. You can achieve the same result by adding 1/12 of your monthly payment as extra principal each month.
• Prepaying a low-rate mortgage instead of investing: If your mortgage rate is 3% and you can earn 7% investing, prepaying the mortgage costs you wealth in the long run. At 2026 rates of 6.5% or higher, the math tilts more toward prepayment. Always compare your loan rate against your expected investment return.

Frequently Asked Questions

Q: Does my loan balance go down the same amount each month? A: No. Each month, slightly more goes to principal and slightly less to interest. The balance reduction accelerates over time. In the early years, only a small fraction of each payment reduces your balance. On a $300,000 loan at 6.5%, the principal portion of payment 1 is $271. By year 15, it is $717. By year 25, it is $1,371.

Q: How do I find out how much of my payments have gone to principal vs. interest so far? A: Your lender sends a year-end Form 1098 showing total mortgage interest paid, which is deductible for many homeowners who itemize. Your amortization schedule also tells you cumulative interest paid at any point. Your monthly statement shows your current balance.

Q: Is paying extra principal always a good idea? A: Usually yes for high-interest debt, but not always the optimal financial decision. If your mortgage rate is 3.5% and you can earn 7% investing, you may generate more wealth by investing extra dollars rather than prepaying the mortgage. At 2026 rates of 6.5% or higher, prepaying becomes more attractive. Always compare your loan's interest rate against your expected investment return. Our blog post on paying off your mortgage vs. investing in your 50s walks through this tradeoff in detail.

Q: What happens if I refinance mid-loan? A: Refinancing creates a new loan with a new amortization schedule starting at full term (e.g., a new 30-year schedule). Even at a lower interest rate, resetting the clock means you restart the front-loaded interest phase. This is why some borrowers refinance into a 15-year loan to avoid paying decades of interest again.