Mortgage Amortization Calculator

Generate detailed mortgage schedules with yearly summaries

Mortgage Details
Mortgage Summary
Monthly Payment: $0.00
Total Payments: 0
Total Interest: $0.00
Payoff Date: -

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What is Mortgage Amortization?

Mortgage amortization is the process of paying off your home loan through regular monthly payments over the loan term. Each payment includes both principal (the amount borrowed) and interest (the cost of borrowing).

In the early years of a mortgage, most of your payment goes toward interest. As you pay down the principal, more of each payment goes toward reducing your loan balance. Understanding this helps you see how extra payments can dramatically reduce total interest.

How to Use This Calculator

Step 1: Enter your mortgage loan amount.
Step 2: Input your current or expected interest rate.
Step 3: Select your loan term (15 or 30 years most common).
Step 4: Set your loan start date.
Step 5: Click "Calculate" to see payment details and yearly summaries.

Understanding Your Mortgage Payments

Your monthly mortgage payment stays the same with a fixed-rate loan, but how it's split between principal and interest changes over time:

  • Year 1: Most goes to interest (e.g., 80% interest, 20% principal).
  • Year 15: About evenly split (50% interest, 50% principal).
  • Year 25: Most goes to principal (20% interest, 80% principal).

This is why early extra principal payments have such a big impact—they reduce the balance that future interest is calculated on.

Who Uses This Calculator?

  • First-Time Buyers – understanding their future payment structure.
  • Current Homeowners – tracking their equity buildup.
  • Refinancers – comparing new loan terms to current mortgage.
  • Extra Payment Planners – seeing impact of additional principal payments.
  • Tax Planners – estimating annual interest deductions.

Mortgage Payment Strategies

  • Make one extra payment per year to cut years off your mortgage.
  • Round up payments to the nearest $100 for easy extra principal.
  • Switch to biweekly payments (26 half-payments = 13 full payments/year).
  • Apply windfalls (tax refunds, bonuses) directly to principal.
  • Refinance to a shorter term when rates drop.

Frequently Asked Questions

Why do I pay so much interest at the beginning?
Interest is calculated on your remaining balance. Early on, your balance is highest, so interest charges are largest. As you pay down principal, the interest portion of each payment decreases.
How much interest will I pay over the life of my mortgage?
On a typical 30-year mortgage, you'll often pay as much or more in interest than the original loan amount. A $400,000 loan at 7% costs about $558,000 total—$400,000 principal + $558,000 interest.
When will I pay more principal than interest?
For a 30-year mortgage at 7%, this crossover happens around month 190 (year 16). For a 15-year loan, it happens much sooner, around month 50 (year 4).
How does my credit score affect my mortgage rate?
Higher scores get lower rates. On a $400,000 loan, the difference between a 740 score (6.5%) and 680 score (7.5%) is about $250/month and $90,000 over 30 years.
Should I choose a 15-year or 30-year mortgage?
15-year mortgages have higher payments but significantly lower total interest and build equity faster. Choose if you can comfortably afford the payment. 30-year offers payment flexibility with the option to pay extra.
Is it worth refinancing my mortgage?
Refinancing makes sense if you can reduce your rate by at least 0.5-1% and plan to stay in the home long enough to recoup closing costs. Use a refinance calculator to determine your break-even point.
How much equity do I have after 5 years?
On a $400,000, 30-year loan at 7%, after 5 years you've paid about $28,000 in principal (7% of the loan). On a 15-year loan, you'd have paid about $95,000 (24% of the loan).
Can I deduct mortgage interest on my taxes?
Yes, if you itemize deductions. You can deduct interest on up to $750,000 of mortgage debt ($1 million if purchased before Dec 15, 2017). This calculator shows your annual interest for tax planning.
What is private mortgage insurance (PMI)?
PMI is required if your down payment is less than 20%. It protects the lender if you default. Costs 0.3-1.5% of loan amount annually. Automatically drops off when you reach 20% equity.
How do extra payments affect my amortization?
Extra principal payments immediately reduce your balance, which reduces interest on all future payments. Even $100/month extra can save tens of thousands and cut years off your mortgage.
What's the difference between fixed and ARM amortization?
Fixed-rate mortgages have predictable, unchanged schedules. ARMs (Adjustable Rate Mortgages) start with fixed rates then adjust periodically, making long-term amortization schedules estimates rather than guarantees.
Should I pay points to lower my rate?
Paying discount points (1% of loan = 0.25% rate reduction typically) makes sense if you'll keep the loan beyond the break-even point. Calculate: Points Cost ÷ Monthly Savings = Months to Break Even.