Free Loan Analysis Tool
Free Amortization Calculator — See Principal vs. Interest Every Month
Visualize exactly how each mortgage payment splits between principal and interest over the life of the loan — free, no signup, updated instantly as you change the numbers.
Principal vs interest on a $400,000 loan at 6.5% over 30 years
The first years of a mortgage are mostly interest by design. Seeing the whole schedule on one chart tells you what a shorter term or an extra payment is actually worth — before you sign.
How to Use the Calculator
Simple inputs, powerful insights
Enter Loan Details
Input your loan amount, interest rate, and term length
View Payment Breakdown
See month-by-month principal and interest distribution
Understand the Timeline
Visualize how payments shift from interest to principal over time
Plan Your Strategy
Use insights to decide on extra payments or refinancing
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Adjust the inputs below to see your loan payment breakdown over time
Loan Parameters
Loan Amortization Schedule
How each payment splits between principal and interest
Loan Amount
$400,000
Interest Rate
6.5%
Loan Term
30 years
Total Interest
$510,178
Disclaimer: Figures are estimates generated from third-party market data and the assumptions provided, for informational purposes only — not an appraisal and not financial, legal, or tax advice. Actual prices, rents, costs, and returns can differ materially. Verify key figures independently and consult qualified professionals before making investment decisions.
The Same $400,000 Loan, Two Terms — Watch the Interest Change
The live chart at 6.5%: first over 30 years, then over 15, so the trade-off between a lower payment and a far lower total interest cost is visible on the page.
Loan Amortization Schedule
How each payment splits between principal and interest
Loan Amount
$400,000
Interest Rate
6.5%
Loan Term
30 years
Total Interest
$510,178
30-Year Term
Lower Payment, Interest-Heavy for Years
At 30 years the payment is $2,528 a month, and the chart shows where it goes: in month 1 about $2,167 is interest and $362 principal. The interest area dominates for more than a decade before the principal share takes over. By the final payment the split is $14 interest to $2,515 principal — and total interest over the loan is roughly $510,000, more than the amount borrowed.
- Stacked areas show the principal and interest portions of every month's payment
- Hover any month for the exact principal, interest and remaining balance
- The crossover point — where principal overtakes interest — is visible on the chart
- Change amount, rate or term and the whole schedule redraws instantly
15-Year Term
Higher Payment, About $283,000 Less Interest
Switch to 15 years and the payment rises to about $3,484 a month — but the interest area collapses. Principal overtakes interest within the first few years instead of after a decade, and total interest falls to roughly $227,000 — about $283,000 less. That is the number to weigh against the extra $956 a month: the calculator puts both in front of you.
- Compare terms on the same loan to see the total-interest difference
- Understand why a shorter term builds equity so much faster — it is the same math the Equity Calculator uses
- A quick way to test refinance scenarios: new rate, new term, new schedule
- Free to run as many times as you like, with no account
Loan Amortization Schedule
How each payment splits between principal and interest
Loan Amount
$400,000
Interest Rate
6.5%
Loan Term
15 years
Total Interest
$227,197
What is Amortization?
Understanding how your mortgage payments work
Amortization is the process of paying off a loan through regular monthly payments over a set period of time. Each payment includes both principal (the amount you borrowed) and interest (the cost of borrowing).
The Key Insight
Early in your loan, most of your payment goes toward interest. As time goes on, more of each payment goes toward paying down the principal. By the end of the loan, your payments are almost entirely principal.
How It Works: A $400,000 Example
Year 1 Payment
Year 30 Payment
Why This Matters for Investors
- •Early Payoff Considerations: Making extra payments early in the loan saves more interest than later payments
- •Cash Flow Planning: Understanding your principal paydown helps calculate true ROI
- •Refinancing Timing: Know how much principal you've paid to evaluate refinancing opportunities
- •Total Interest Cost: See the total amount you'll pay in interest over the loan's lifetime
Real-World Example
$400,000 loan at 6.5% for 30 years
Payment Evolution Over Time
Total Loan Cost Summary
Key Takeaway: You'll pay $510,178 in interest over 30 years - that's 128% of the original loan amount!
This is why making extra principal payments early can save significant money.
Powerful Features, Completely Free
Professional amortization analysis without the professional price tag
Visual Chart
Interactive stacked area chart showing payment breakdown over time
Month-by-Month
Hover over any month to see exact principal and interest amounts
Payment Schedule
See how early payments are mostly interest, later ones mostly principal
Multiple Scenarios
Compare different loan terms to see total interest paid
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Understanding Loan Amortization for Real Estate Investors
Every mortgage payment you make includes two components: principal (reducing your loan balance) and interest (the cost of borrowing). Understanding how these shift over time is crucial for real estate investors because it affects your equity buildup, refinancing decisions, and true ROI calculations.
In the early years of a loan, most of your payment goes to interest - this is by design. As your balance decreases, the interest portion shrinks and more goes to principal. This "front-loaded interest" means extra payments early in the loan save far more money than the same payments made later.
What is Loan Amortization?
Amortization is the process of spreading a loan into equal monthly payments over a set term, where each payment covers both interest and principal. An amortization schedule shows exactly how much of each payment goes to interest vs principal throughout the loan's life.
Why Does More Go to Interest Early On?
Interest is calculated on your remaining balance. With a larger balance in early years, you pay more interest. Example: On a $400,000 loan at 6.5%, month 1 pays ~$2,167 interest and ~$362 principal. By year 15, it shifts to ~$1,577 interest and ~$951 principal. Same payment, different allocation.
How Does Loan Term Affect Total Interest Paid?
A 30-year loan has lower monthly payments but you pay significantly more total interest. A 15-year loan has higher payments but saves tens of thousands in interest. On $400,000 at 6.5%: 30-year pays ~$510K interest; 15-year pays ~$227K - a difference of about $283,000.
Should Real Estate Investors Pay Extra Principal?
It depends on opportunity cost. If rental properties generate 10%+ returns, investing extra cash in new properties may beat the 6-7% you'd save paying down your loan. However, paying down principal builds equity faster, improves debt ratios for future loans, and reduces risk.
Frequently Asked Questions
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