Extra Payment Loan Payoff
See how much interest and time you save by paying extra on your mortgage or loan each month. Full amortization comparison — no sign-up required.
Added May 9, 2026 · Updated Aug 12, 2026
Input
Result
Enter a value for current loan balance to see your result.
How it works
Calculates how much time and interest you save by adding a fixed extra amount to your monthly loan payment. Runs a full month-by-month amortization with and without the extra payment to find the exact payoff difference.
Formula
Payment = P · r / (1 − (1 + r)^(−n)) then iterate with extra each month
- P
- Remaining loan balance
- r
- Monthly rate (annual rate ÷ 12 ÷ 100)
- n
- Remaining months (years × 12)
- extra
- Additional principal paid each month
Step by step
- 01Calculate the standard monthly payment from the remaining balance, rate, and term.
- 02Run a baseline amortization at the standard payment to find total interest with no extra payment.
- 03Re-run the amortization adding the extra payment to the standard payment each month.
- 04Count the months until the balance hits zero — that is the new payoff date.
- 05Subtract new total interest from baseline total interest to get interest saved.
Examples
$250k at 6.5% · 30 yr · $200 extra/mo
Adding $200/month to a 30-year $250k loan at 6.5% saves over $58,000 in interest and cuts the loan by roughly 5 years.
Inputs
- Current loan balance:
- 250000
- Annual interest rate:
- 6.5
- Remaining term:
- 30
- Extra payment per month:
- 200
Result
- Interest saved:
- 58143.73
$20k auto loan · 7% · 5 yr · $100 extra
An extra $100/month on a 5-year auto loan at 7% saves about $605 in interest and pays the car off roughly 10 months early.
Inputs
- Current loan balance:
- 20000
- Annual interest rate:
- 7
- Remaining term:
- 5
- Extra payment per month:
- 100
Result
- Interest saved:
- 605.24
Frequently asked questions
Does it matter when I start making extra payments?
Yes — extra payments made early in a loan save significantly more interest than the same payments made later, because interest accrues on a larger remaining balance. Starting extra payments in year 1 vs year 10 can double the savings.
Will my lender apply the extra amount to principal?
Most lenders do, but some may apply it to future payments instead. Always mark extra payments as 'principal reduction' in your payment instructions or log in to verify how your lender applies them.
What if I can only pay extra occasionally, not every month?
This calculator models a consistent extra payment each month. For one-time lump-sum payments, the actual savings will be proportional but not exactly the same; use the amortization schedule tool to model specific lump-sum scenarios.
Does the standard monthly payment change?
No. The extra payment is on top of your existing required monthly payment. The required payment stays fixed; only the payoff date changes.
Should I pay off my loan early or invest instead?
It depends on your loan interest rate vs. expected investment returns and risk tolerance. Paying off debt is a guaranteed return equal to your interest rate; investing offers potentially higher but variable returns. Many people split the difference.