Auto Refinance Calculator

Compare current vs new auto-loan payments, break-even point, and total lifetime interest — including the term-extension trap.

Current Auto Loan

New Auto Loan

Your Auto Refinance Analysis

Current Monthly Payment
$0
New Monthly Payment
$0
Monthly Savings
$0
Break-Even Point
0

Monthly Payment Comparison

Current Loan
New Loan

Lifetime Interest Breakdown

Current Total Interest
$0
New Total Interest
$0
Refinance Fees
$0
Net Lifetime Savings
$0

How auto refinancing actually works

Auto refinancing replaces your existing car loan with a new one — typically with a lower interest rate, a different term, or both. The new lender pays off your old loan, files a fresh lien with your state DMV, and you begin making payments to the new lender. Unlike a mortgage refinance, there is no escrow, no PMI, no points, no appraisal in most cases, and fees are normally under $500 total.

Because auto loans are short (typically 24–84 months) and balances are small relative to mortgages, the math leans on three numbers: monthly savings, break-even months, and net lifetime savings. The first two get advertised everywhere. The third is what actually matters.

When auto refinancing makes sense

When refinancing does NOT make sense

The term-extension trap (the most common mistake)

If you have 36 months left on your current loan at 9% and refinance into a new 60-month loan at 6%, your monthly payment can drop 25–40%. That feels like an obvious win — and on monthly cash flow it is. But you have just reset the amortization clock from 36 months back to 60 months. Even at the lower rate, paying interest for 24 extra months can produce more total lifetime interest than the original 9% loan would have.

The calculator above surfaces this with the Net Lifetime Savings line. If that number is negative, the green "favorable" banner will not fire even when monthly savings are positive — instead you will see the term-extension warning, with the dollar amount of extra interest you are signing up for. Lower monthly payments are not the same as saving money.

OBBBA §70402 and the new 2026 auto-loan-interest deduction

The One Big Beautiful Bill Act (Pub. L. 119-21, signed July 4 2025) added a temporary above-the-line federal income-tax deduction of up to $10,000 per year for interest paid on loans secured by qualifying U.S.-assembled new passenger vehicles purchased between Jan 1 2025 and Dec 31 2028. The new IRC §163(h)(4) deduction phases out for AGI above $100,000 (single) / $200,000 (MFJ).

Critically: the deduction applies only to new-vehicle purchase financing. Refinancing a qualifying purchase loan generally preserves the deduction if the refinance loan is secured by the same vehicle and the new principal does not exceed the remaining purchase-debt balance — but refinancing a used-vehicle loan, refinancing into a non-purchase-money loan, or rolling negative equity into the new loan can disqualify all or part of the interest. If you bought your car before Jan 1 2025 or bought used, this deduction does not apply at all.

Check with a CPA before assuming a refinance preserves §163(h)(4) treatment. This calculator does not model the deduction's tax benefit — it reports pre-tax interest only.

Auto refinance fees: what to actually expect

The default $200 in the calculator is a realistic estimate for a typical credit-union refinance with a moderate state title fee. Plug in your own number once you have a Loan Estimate from a specific lender.

Step-by-step: how to refinance an auto loan

Frequently Asked Questions

How does the auto refinance calculator work?
The calculator uses the standard fixed-rate amortization formula (M = P·r·(1+r)^n / ((1+r)^n − 1)) twice — once for your current auto loan and once for the new loan — and then compares monthly payments, total lifetime interest, and the break-even point on any refinance fees. P is your current loan balance, r is the monthly interest rate (APR ÷ 12), and n is the number of months. Closing-cost amortization is straight-line (closingCosts ÷ monthlySavings).
What is the term-extension trap on auto refis?
If you have 36 months left on your current loan and refinance into a new 48- or 60-month loan at a lower rate, the lower monthly payment can be misleading. You may pay more interest over the life of the new loan than you would have paid by keeping the old loan, because you reset the amortization clock. The calculator surfaces this as a "net lifetime savings" line — always check that number, not just the monthly savings. If net lifetime savings is negative, your monthly cash flow improves but you are paying more total interest.
How much can refinancing my car loan save me?
Savings depend on your current rate, the new rate, your remaining balance, and whether you keep the same term or extend. As a rough guide: a 1.5–2.5 percentage-point rate drop on a $25,000 balance with 36 months remaining typically saves $400–$1,200 in lifetime interest if you keep the same remaining term, or "feels like" $40–$80 per month in cash-flow savings if you extend. Plug your real numbers into the calculator above for an exact estimate.
What credit score do I need to refinance an auto loan?
Most auto-refinance lenders look for a minimum FICO of 600–640 for approval, but the lowest advertised rates typically require a 720+ score. Subprime borrowers can sometimes refinance after rebuilding credit for 12–18 months from the original purchase. Check your free credit report at AnnualCreditReport.com before applying, and dispute any errors first — a 20-point bump can move you across a pricing tier.
Are there fees to refinance a car loan?
Auto refinance fees are typically much smaller than mortgage refinance fees — usually $0–$500 total. Possible fees: state title transfer ($15–$100), lender origination ($0–$300 — most online lenders charge $0), state lien-recording fee ($10–$50). Watch for prepayment penalties on your existing loan in a handful of states (Alabama, Florida, Massachusetts, Michigan, Pennsylvania, Virginia historically allowed them; check your loan documents).
Can I deduct auto-loan interest in 2026?
Generally no for personal-use vehicles — auto-loan interest on personal cars has not been deductible since the 1986 Tax Reform Act repealed it. However, the One Big Beautiful Bill Act (OBBBA, Pub. L. 119-21, signed July 4 2025) added a temporary above-the-line deduction of up to $10,000 per year for interest on loans secured by qualifying U.S.-assembled new vehicles purchased Jan 1 2025 through Dec 31 2028, under new IRC §163(h)(4). The deduction phases out for AGI above $100k single / $200k MFJ. Used-vehicle interest, lease interest, and refinance-of-used-loan interest do NOT qualify. If you use the vehicle for business, the business-use portion of interest is deductible on Schedule C separately.
How long does an auto refinance take?
Most online auto refinances close in 2–10 business days from application — much faster than mortgage refinances. The slowest step is usually your current lender releasing the lien and the new lender filing it with your state DMV. Keep making your current payment until you have written confirmation that the new lender has paid off the old loan.
When should I NOT refinance my auto loan?
Avoid refinancing if (a) you have fewer than 12 months remaining on the current loan — fees and friction outweigh savings; (b) the new loan extends your term and the net lifetime savings shown by the calculator is negative; (c) your car is significantly underwater (loan balance > car value) and the new lender will not finance the negative equity; (d) your current loan has a prepayment penalty that exceeds the projected savings; (e) you are within 60 days of a major credit event (new mortgage, large credit-card balance) that could lower your score and the offered rate.

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⚠️ Disclaimer: This calculator provides estimates for educational and informational purposes only. Results are not financial advice and should not be relied upon for making financial decisions. Actual results may vary based on individual circumstances, lender pricing, state-specific fees, and tax treatment. Always consult a qualified financial advisor, CPA, or licensed loan officer before refinancing. CalcLeap is not a financial institution and does not provide financial advisory services.