Car Loan Refinance Calculator
Compare your current car loan with a proposed refinance and estimate the new payment, remaining interest, fees, and total savings. This Auto Refinance Calculator puts both loans side by side so you can see whether a lower rate is worth it.
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Compare total cost, not payment alone
Extending a loan can reduce the monthly payment while increasing the total amount paid. Include lender fees and check for any prepayment terms.
How a car loan refinance calculator works
A car refinance calculator models two loans on the same debt. The first is the car loan you already have, priced at its current APR over the months you have left. The second is the loan you are being offered, priced at its new APR over its new term, plus any refinance fees. Each loan's monthly payment comes from the standard amortizing-payment formula, and its total interest is simply every payment added up minus the balance you owe today.
Because both sides start from the same payoff balance, the difference between them is the estimated car loan refinance savings. That is why an auto loan refinance calculator needs your payoff balance and remaining months rather than the original loan amount and original term.
How APR and remaining loan balance affect refinancing
APR sets the price of the money you still owe, and the balance sets how much of it is exposed to that price. Both matter, and they pull in the same direction: a three-point rate cut on a $25,000 balance with four years to run is worth far more than the same cut on a $6,000 balance with eight payments left. Late in a loan, most of the remaining payments are principal rather than interest, so there is less interest left for a lower rate to remove. This is the usual reason a refinance that looks attractive on paper barely moves the total.
Why a lower monthly payment does not always mean greater total savings
Monthly payment and total cost are two different results, and a refinance can improve one while worsening the other. Restarting the loan over a longer term divides the same balance into more payments, so each payment shrinks — but interest keeps accruing for those extra months. The monthly difference can be clearly positive while total savings are negative. When you refinance a car loan, read the total savings figure first and treat the payment change as a cash-flow question.
How refinance fees affect savings
Title transfer, lien recording, and lender or registration fees are paid up front but are recovered slowly out of the interest you avoid. The calculator adds them to the new loan's cost, so they come straight off your savings. A useful check is the break-even point: divide the fees by the monthly interest you are saving. If the fees take longer to recover than you plan to keep the car, the refinance is unlikely to pay off.
Worked example
Suppose you owe $18,000 at 9.5% APR with 36 months remaining. That is a payment of about $577 per month and roughly $2,757 in interest still ahead of you.
Refinance that balance at 6.5% for 36 months with $300 in fees and the payment falls to about $552. Interest plus fees on the new loan comes to about $2,161, so you save roughly $597 overall — a small payment change, but real money saved.
Now take the same 6.5% rate over 48 months instead. The payment drops to about $427, which is nearly $150 less each month, yet interest plus fees rises to about $2,790 — about $32 more than simply keeping your current loan. Same rate, same fees, same balance; the extra twelve months cancelled the entire benefit. Enter both versions above to see the comparison for your own numbers.
When comparing an existing car loan with a refinance may be useful
Running the comparison is worth the few minutes when your credit score has improved since you bought the car, when you financed at the dealership without shopping the rate, when market rates have fallen, or when a promotional rate is ending. It also helps when a payment has become hard to afford — in that case the calculator shows exactly what the relief costs you in total interest, so the trade-off is a decision rather than a surprise. It is less likely to help if you are close to paying the loan off, if you owe significantly more than the car is worth, or if your current loan carries a prepayment penalty. Checking how far your car has depreciated is a quick way to see where you stand.
Car loan refinance calculator FAQ
How does a car loan refinance calculator work?
It compares two amortizing loans on the same balance: your current car loan over its remaining months, and the proposed loan at its new APR and term. Total interest for each is the sum of payments minus the balance, and any refinance fees are added to the new loan's cost.
Does refinancing a car loan always save money?
No. A refinance saves money when the interest you avoid is larger than the interest and fees on the new loan. Lowering the APR but stretching the term over more months can increase what you pay overall.
Why is my monthly payment lower but my savings negative?
A longer term spreads the same balance over more payments, so each one is smaller while interest accrues for longer. The calculator reports total savings, which can be negative even when the monthly difference is positive.
What balance should I enter?
Use your current payoff balance from your lender rather than the original amount financed, and enter the number of months left on the loan rather than its original term.
Should I include refinance fees?
Yes. Title, lien, and lender fees are subtracted from your savings, so entering them shows whether a small rate reduction is still worth it.
Estimates use standard amortization and your entered figures. See our calculation methodology for the assumptions behind TutorCalc results, and confirm any payoff quote and fee with your lender.