How loan payoff calculator works
Enter your loan principal, annual interest rate, and either the loan term in years or your scheduled monthly payment. The calculator derives the standard amortization schedule — the months and total interest it takes to pay the loan off with the scheduled payment alone.
Add an extra monthly payment on top of the scheduled payment. The calculator runs the schedule again with that extra amount applied to principal each month and reports the new payoff time and total interest.
The difference between the two schedules is your savings: months (and years) shaved off the loan and the interest you no longer pay. Extra payments go to principal, so the loan ends sooner and every skipped month also skips its interest.
Frequently asked questions
How do extra payments reduce a loan?
Each month your scheduled payment first covers the interest accrued, and the rest reduces principal. An extra payment is applied entirely to principal, so the balance drops faster. A lower balance means less interest accrues the next month, which snowballs until the loan is paid off early.
Should I enter my term in years or my monthly payment?
Either. Enter the loan term in years and the calculator works out the scheduled monthly payment from the principal and rate. If you already know your monthly payment (for example from a statement), enter that instead and leave the years field blank.
Does this work for mortgages and car loans?
Yes. It models any amortizing loan with a fixed monthly payment and a fixed interest rate — mortgages, car loans, personal loans, and student loans. It does not model adjustable rates or interest-only periods.
What if my payment does not cover the interest?
If the scheduled payment is too small to cover the monthly interest, the balance would grow rather than shrink and the loan can never be paid off. The calculator flags this as payoff-not-possible so you know the payment needs to increase.
