Amortization Schedule
An amortization calculator reveals the hidden mechanics behind every fixed-rate loan payment. While your monthly payment stays the same throughout the loan term, the split between principal and interest shifts dramatically over time—early payments are almost entirely interest, while later payments go mostly toward reducing the balance. This calculator generates a complete payment schedule so you can see exactly where every dollar goes. Amortization schedules are critical for anyone carrying a mortgage, auto loan, or personal loan. By seeing the full breakdown, you can make strategic decisions about extra payments, understand how refinancing changes your trajectory, and accurately calculate the remaining balance at any point during the loan. Many borrowers are surprised to discover that on a 30-year mortgage, they pay more in interest during the first decade than they do in principal reduction. Use this calculator to compare different loan terms, evaluate the impact of making extra principal payments, and understand the true cost of borrowing over the full life of a loan.
Real-World Examples
30-Year Mortgage Breakdown
$250,000 loan at 6.5% for 30 years. Monthly payment: $1,580. In the first payment, $1,354 goes to interest and only $226 to principal. By year 15, the split is roughly equal. Total interest over 30 years: $319,000—more than the original loan amount.
5-Year Auto Loan
$35,000 car loan at 5.9% for 5 years. Monthly payment: $675. First payment: $172 interest, $503 principal. By the final year, only $20/month goes to interest. Total interest: $5,500.
Extra Payment Impact
On the $250,000 mortgage above, adding $200/month extra to principal reduces the loan term from 30 to 22.5 years and saves approximately $98,000 in total interest.
Tips & Notes
In the first year of a 30-year mortgage, roughly 70-80% of each payment goes to interest—making extra principal payments early has the greatest long-term impact.
Biweekly payments (half the monthly amount every two weeks) result in 13 full payments per year instead of 12, shortening a 30-year mortgage by approximately 4 years.
When comparing loan offers, look at the total interest paid over the loan life, not just the monthly payment amount.
If you receive a lump sum (bonus, inheritance), applying it to loan principal early in the term maximizes interest savings.
Amortization tables can reveal the break-even point for refinancing—the month when your new loan's lower interest savings exceed the refinancing costs.
Common Mistakes to Avoid
Assuming equal portions of each payment go to principal and interest. In reality, early payments are heavily weighted toward interest.
Extending the loan term to lower monthly payments without realizing the total interest cost may double or triple.
Forgetting to verify that extra payments are applied to principal reduction rather than being held for future payments by the lender.
Not realizing that when you refinance and reset to a new 30-year term, you restart the amortization schedule with high-interest payments.
Ignoring that negative amortization loans (where payments do not cover interest) cause the loan balance to actually increase over time.
Frequently Asked Questions
What does amortization mean?
Amortization is the process of spreading a loan into a series of fixed payments over time. Each payment includes both interest (the cost of borrowing) and principal (the loan balance reduction). The word comes from the Latin "amortire," meaning to bring to death—you are gradually killing the debt.
Why do early payments mostly go to interest?
Interest is calculated on the remaining balance. With a large balance early in the loan, the interest charge is high, leaving little room in the fixed payment for principal. As the balance decreases, interest charges shrink and more of each payment reduces the principal.
How much does one extra payment per year save?
One extra monthly payment per year on a $250,000 mortgage at 6.5% saves approximately $65,000 in interest and shortens the loan by about 4.5 years. The savings are proportionally similar for most fixed-rate loans.
What is the difference between amortization and depreciation?
Amortization refers to paying off a loan over time through regular payments, or spreading the cost of an intangible asset. Depreciation refers to the decrease in value of a tangible asset over time. Both spread costs over a period, but they apply to different contexts.
Can I see how much principal I have paid at any point?
Yes. The amortization schedule shows the remaining balance after each payment. Subtract the remaining balance from the original loan amount to find total principal paid. This is useful for calculating home equity or understanding how much you still owe.
Does amortization apply to all loan types?
Fixed-rate loans (mortgages, auto loans, personal loans) follow standard amortization. Credit cards, lines of credit, and adjustable-rate mortgages may use different structures. Interest-only loans do not amortize during the interest-only period.