What Is an Amortization Schedule?
An amortization schedule is a complete table of every loan payment, showing how each payment is split between principal and interest, and the remaining loan balance after each payment. Generating an amortization schedule is one of the most revealing exercises in personal finance — it shows exactly how much of your payment actually reduces what you owe vs. how much goes to the lender as interest.
The Front-Loaded Interest Problem
Amortizing loans are front-loaded with interest. On a 30-year mortgage at 7%, roughly 78% of your first payment is interest. By the midpoint (year 15), the split reaches roughly 50/50. In the final years, almost all of each payment is principal. This structure is mathematically inevitable: interest is calculated on the outstanding balance, which is highest at the start of the loan.
The Power of Extra Payments
Because early payments are mostly interest, extra principal payments made early in the loan have an outsized impact. Every extra dollar of principal paid today eliminates future interest on that dollar for the remaining term. For a $300,000 30-year mortgage at 7%, paying an extra $200/month from month one saves approximately $60,000 in interest and pays off the loan about 5 years early.
Annual Summaries
The full schedule shows monthly detail, but annual summaries let you see your progress at a glance: how much total principal you've paid each year, how much interest you've paid, and what your remaining balance is. These numbers are also useful for tax planning — mortgage interest paid is the figure you'd report on Schedule A if itemizing deductions.
Using the Schedule for Refinancing Decisions
An amortization schedule reveals the right time to refinance. In the early years, when interest is highest, a rate reduction saves more. Later in the loan, you've already paid most of the interest and refinancing into a new 30-year term would restart the front-loaded interest cycle. Compare your current schedule against a new loan schedule before refinancing.
Works for Any Loan Type
This calculator generates schedules for mortgages, car loans, personal loans, student loans, or any fixed-rate fully amortizing loan. Simply enter the balance, rate, and term. For adjustable-rate loans, use your current rate to model the current period's schedule.