Auto loan refinance calculator
A refinance offer's lower payment is easy to buy and easy to misread: a longer term lowers it on its own, with no rate improvement required. This holds the term constant to isolate the rate, then shows the offer as actually written.
Worked example — Term-matched, this refinance saves: $1,310. $21,000 at 9.4% refinanced to 6.2% over the same 42 months, no fees
Price your own auto loan refinance
Enter what you owe, your current rate and months left, and the offer. The headline number holds the term fixed at the months you have left, because that is the only comparison in which the rate is the only thing that changed. The offer as actually written is shown next to it, not folded into the same figure.
$21,000 at 9.4%, offer matched to 42 months: 42 months left on the current loan, refinanced into the same 42-month term at the offered rate. The rate is the only thing that changes.
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The gold line is what staying on your current loan costs in interest. Every point on the blue curve is the same offered rate at a different term: the term-matched point sits at 42 months, and your offer sits at 42 months.
Should I refinance my car loan?
On the numbers above, $21,000 at 9.4% with 42 months left, refinanced to 6.2% over the same 42 months, saves $1,310 in interest and lowers the payment by $31 a month. With no fees the saving starts immediately; add a fee and the break-even is fees divided by that monthly payment drop, not by whatever the offer's own payment happens to be. A refinance is worth doing when the offered rate is genuinely lower and the months left are enough for the saved interest to clear whatever it costs to get it.
Term-matched refinance vs the offer's longer term
The same $21,000 balance and the same 6.2% offer, written over 60 months instead of the 42 you actually have left, drops the payment by another $150 a month, to $408. That extra payment relief is not free: at the identical 6.2% rate, the longer term alone adds $1,062 of interest compared with matching your current term. The rate made the loan cheaper; the extra 18 months made it more expensive again, and a calculator that only compares payments never shows you that second number.
Am I upside down on my car loan?
You are upside down when you owe more than the car is worth. On $21,000 owed against an $18,500 car, that is $2,500 underwater. A lender refinancing an upside-down loan will typically roll that deficit into the new balance rather than require it paid down first, which raises the loan amount and the payment: term-matched, the payment moves from $557 to $624 on the larger, $23,500 balance. Refinancing does not fix negative equity; it moves it into a new loan at whatever rate you are offered.
Interest saved by rate drop, term-matched
Held at $21,000 and 42 months remaining, term-matched interest saved at each rate drop from the current 9.4% rate, computed from the same solver the calculator above runs.
| Rate drop | New rate | New payment | Interest saved |
|---|---|---|---|
| 0.50 pts | 8.90% | $584 | $208 |
| 1.00 pts | 8.40% | $579 | $414 |
| 1.50 pts | 7.90% | $574 | $620 |
| 2.00 pts | 7.40% | $569 | $824 |
| 2.50 pts | 6.90% | $564 | $1,027 |
| 3.20 pts | 6.20% | $557 | $1,310 |
Every row holds the term at 42 months, so the saving in the last column is caused by the rate drop alone. A lender's own payback pitch usually compares payments on whatever term they are offering, which is why the same rate drop can be advertised at a bigger-looking monthly number once the term is allowed to move too.
The next question after this one
Car affordability calculatorCalculatorWhat the loan should have been sized to in the first place, under the same 20/4/10 discipline this refinance is now working around.Open nextOther questions
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More calculators for the same decision
The car affordability calculator prices what a lender's 20/4/10 rule actually allows before you buy, and the extra payment calculator shows what paying ahead does to the loan you already have.