How this works
Standard auto refi math: new monthly payment vs current, multiplied across remaining months, less fees, gives you total savings (or cost).
The trap most calculators don't flag: if you're underwater on the existing loan — owe more than the car is worth — most refi lenders won't touch it, and the ones that will charge a premium rate. The calculator below checks your loan-to-value and flags underwater status.
The other trap: "Lower your payment!" by extending the loan to 72 months when you only had 42 left. Your monthly drops, but you pay interest for 30 extra months. Total cost is higher. The verdict factors in whether the new term is longer than current.
The honest verdict logic
- ✅ Refinance: rate drops 2%+, term doesn't extend, not underwater, fees recouped quickly.
- ⚠️ Marginal: rate drop 1-2%, OR small balance / small fees-to-savings ratio.
- ❌ Skip: underwater, or new term extends meaningfully past current, or rate barely lower.
Related calculators
- Lease vs buy car — if you're approaching loan end and weighing the next vehicle decision.
FAQ
When does auto refi actually save money?
Three things have to be true together: (1) new rate is at least 2% below current, (2) you have 24+ months remaining, (3) you're not underwater. Miss any of those and the math gets shaky.
What does "underwater" mean and why is it a deal-killer?
Underwater = you owe more on the car than it's worth. Most lenders won't refinance an underwater loan, and the ones that will charge a premium rate. The refi math only works on the assumption you could sell the car to pay off the loan if needed.
How long should the new loan be?
Don't extend the loan beyond when you'd want to sell or trade the car. A common trap: "lower payment via 72-month refi" when you only have 30 months left. The new payment is lower but you're paying interest for 3.5 years longer.
Are there fees?
Auto refis usually have title transfer fees ($15-$75) and state-required re-registration fees. Far lower than mortgage refi — but worth checking, especially on small loan balances where fees can eat the savings.
Why do auto refi rates vary so much?
Credit score, vehicle age, and lender all matter heavily. Cars older than 10 years can be hard to refinance at all. Credit-union refi rates are usually 1-2% below online lender rates — check your CU first.
Does shopping refi quotes hurt my credit?
Auto loan rate-shopping inquiries within a 14-day window count as a single inquiry for FICO scoring. Shop aggressively in a short window. Multiple inquiries spread over months DO hurt.