Amortization Calculator
Calculate your monthly loan payment and view a complete amortization schedule showing principal, interest, and remaining balance for every payment.
Extra Payments (Optional)
How to Use This Amortization Calculator
This free amortization calculator helps you understand exactly how your loan payments break down over time. Whether you have a mortgage, car loan, or personal loan, follow these steps to get a full picture of your repayment journey.
Step 1: Enter Your Loan Details
Start by entering the total loan amount you plan to borrow. Next, input the annual interest rate your lender has quoted you. Then select the loan term, which you can specify in either years or months. For a standard 30-year mortgage, enter 30 years. For a 5-year car loan, enter 5 years or 60 months.
Step 2: Add Extra Payments (Optional)
If you plan to make extra payments toward your loan, enter them in the optional section. You can specify a recurring monthly extra payment and a one-time lump sum payment at a specific month. The calculator will show you exactly how much interest you save and how many months earlier you can pay off the loan.
Step 3: Review Your Results
After clicking Calculate, you will see your monthly payment amount, total amount paid over the life of the loan, and total interest charged. The interactive chart shows your remaining balance over time, and the full amortization schedule table breaks down every single payment.
Step 4: Compare Scenarios
Use the Compare Scenarios tab to evaluate two different loan options side by side. This is especially useful when deciding between different loan terms or comparing offers from multiple lenders. You can see at a glance which option saves you more money in interest.
Understanding Amortization
Amortization is the process of spreading a loan into a series of fixed payments over time. Each payment is split between paying off interest and reducing the principal balance. In the early years of a loan, most of your payment goes toward interest. As time goes on, an increasing portion goes toward principal.
This is why making extra payments early in the loan term has such a significant impact. When you reduce the principal early, you reduce the amount of interest that accumulates on every subsequent payment, creating a compounding savings effect.
Amortization Formula Explained
The standard amortization formula for calculating monthly payments is:
M = P * [r(1+r)^n] / [(1+r)^n - 1]
Where M is the monthly payment, P is the loan principal, r is the monthly interest rate (annual rate divided by 12), and n is the total number of payments. This formula ensures that each payment is the same amount, while the split between principal and interest changes over time.
Tips for Saving on Your Loan
- Make biweekly payments instead of monthly. This results in 26 half-payments per year (equivalent to 13 full payments), shaving years off your loan.
- Round up your payment to the nearest hundred dollars. The extra goes directly to principal.
- Put any windfalls like tax refunds or bonuses toward a lump sum extra payment.
- Refinance when rates drop significantly. Use the comparison tool to see if the savings justify closing costs.
- Avoid extending your loan term when refinancing, as this can increase total interest even at a lower rate.
- Check if your loan has prepayment penalties before making extra payments.
Common Loan Types and Typical Terms
Mortgages are most commonly offered as 15-year or 30-year fixed rate loans. Adjustable rate mortgages (ARMs) may start with a lower rate but can change after an initial period. Car loans typically range from 36 to 72 months. Personal loans often run from 12 to 60 months. Student loans can have terms from 10 to 25 years depending on the repayment plan.
Each loan type has different considerations. For mortgages, you may also need to account for property taxes, insurance, and possibly private mortgage insurance (PMI) on top of the principal and interest calculated here. The amortization schedule from this tool focuses on the core loan repayment.
Examples and Impact
Consider a $300,000 mortgage at 6.5% for 30 years. The standard monthly payment is about $1,896. By adding just $200 per month in extra payments, you would save over $90,000 in interest and pay off the loan about 6 years early. A one-time extra payment of $10,000 in the first year saves roughly $30,000 in interest over the life of the loan.
Use the extra payment fields in the calculator above to model your specific situation. Even small additional amounts can make a meaningful difference over decades of repayment.
Community Questions
- How to build an amortization schedule in JavaScript? 10 answers · tagged: javascript, finance, amortization
- Amortization formula for loan payments? 13 answers · tagged: finance, loan, amortization
- How to calculate principal vs interest breakdown? 8 answers · tagged: finance, amortization, calculation
Frequently Asked Questions
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Source: Hacker News
Research Methodology
This amortization calculator tool was built after analyzing search patterns, user requirements, and existing solutions. We tested across Chrome, Firefox, Safari, and Edge. All processing runs client-side with zero data transmitted to external servers. Last reviewed March 19, 2026.
Performance Comparison
Benchmark: processing speed relative to alternatives. Higher is better.
PageSpeed Performance
Measured via Google Lighthouse. Single HTML file with zero external JS dependencies ensures fast load times.
Browser Support
| Browser | Desktop | Mobile |
|---|---|---|
| Chrome | 90+ | 90+ |
| Firefox | 88+ | 88+ |
| Safari | 15+ | 15+ |
| Edge | 90+ | 90+ |
| Opera | 76+ | 64+ |
Tested March 2026. Data sourced from caniuse.com.