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Auto Refinance Calculator

See if refinancing your car loan saves money after fees, with monthly savings, interest saved, and break-even months.

Includes refinance fees in the break-even calculation — the way it should be done.

$
%
%
$
You save each month
+$26/mo
Break-even in 6 months. Net lifetime savings: $1,086.
Current monthly
$547
New monthly
$522
Total interest saved
$1,236
Net savings (after fees)
$1,086
Explain this result

Turn the numbers above into plain-language takeaways. Educational only — not financial advice.

Save & Compare Scenarios

Save the current inputs under a name, then reload or compare them side by side. Scenarios stay on this device only.

Overview

How the Auto Refinance Calculator Works

Refinancing a car loan is worth doing when your credit has improved, when you financed at the dealer without shopping, or when rates have fallen since you signed. It is worth avoiding when the fees exceed the savings or when stretching the term simply hides a higher total cost. This calculator puts both loans side by side, subtracts the refinance fees, and tells you the month at which you are genuinely ahead.

Formula

The Math Behind the Calculator

New Payment = B × r / (1 − (1 + r)^−n) using the current payoff balance B, the new monthly rate r, and the new term n. Monthly Savings = Current Payment − New Payment. Break-even Months = Refinance Fees ÷ Monthly Savings. Net Interest Saved = (Remaining interest on current loan − Interest on new loan) − Fees.

Example

A Worked Example

You owe $22,000 with 42 months left at 11.9%, paying $625 a month. A credit union offers 6.9% over 42 months, which drops the payment to $573 — a $52 monthly saving with $250 in title and lien fees, so you break even in five months and save about $1,930 in interest. Take the same 6.9% over 60 months instead and the payment falls to $434, which feels better but adds roughly $1,100 in extra interest because you are borrowing for 18 months longer.

How to use

How to Use the Auto Refinance Calculator

  1. 1Enter your current payoff balance from the lender, not the original loan amount.
  2. 2Enter your current APR, current monthly payment, and the number of months remaining.
  3. 3Enter the new APR you have been offered in writing and the new term.
  4. 4Add all refinance fees — title transfer, lien recording, and any state registration charges.
  5. 5Try matching the new term to your remaining months first; only extend the term if cash flow, not total cost, is the priority.
Interpretation

What the Results Mean

  • Monthly savings is the immediate cash flow improvement, before fees are recovered.
  • Break-even months tells you how long you must keep the car for the refinance to be worthwhile.
  • Net interest saved is the honest number — it already accounts for fees and for any change in term.
  • A negative net saving with a positive monthly saving means you have lowered the payment by extending the loan and are paying more overall.
Keep exploring

Smart Next Steps

What to explore next
Avoid

Common Mistakes to Avoid

  • Extending the term to cut the payment and quietly increasing total interest paid.
  • Refinancing when you are already upside down, since most lenders will not finance more than the vehicle is worth.
  • Ignoring a prepayment penalty or precomputed interest structure on the existing loan.
  • Applying at many lenders over a long window instead of clustering applications into a 14-day rate-shopping period.
  • Refinancing a car you plan to sell within a few months, so the fees never get recovered.
Scope

Limitations of This Calculator

  • It assumes simple-interest amortization. Precomputed interest loans, still used by some subprime lenders, do not behave this way.
  • Prepayment penalties on the existing loan are not modeled.
  • It does not check loan-to-value, and lenders typically decline refinances above about 110–125% LTV.
  • GAP insurance and extended warranty refunds or transfers are excluded.
  • The rate you enter is assumed to be the rate you are approved for; actual offers depend on credit, vehicle age, and mileage.
Keep going

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FAQ

Frequently Asked Questions

When is auto refinancing worth it?+

Generally when you can cut the APR by at least two points, you have more than a year of payments left, and you will keep the car well past the break-even month shown here.

Does refinancing hurt my credit score?+

There is a small temporary dip from the hard inquiry and the new account. Multiple auto inquiries within a 14-day window are usually treated as one for scoring purposes.

Can I refinance if I owe more than the car is worth?+

It is difficult. Most lenders cap loan-to-value around 110–125%, so being significantly underwater usually means waiting until the balance falls.

Should I keep the same term or extend it?+

Keep the same remaining term if you can afford it — that captures the rate saving without adding interest. Extend only if you need the cash flow and accept the higher total cost.

What fees are involved?+

Usually modest: title transfer and lien recording, typically $50–$400 depending on the state. Some lenders charge nothing at all.

Financial Disclaimer

This calculator is for educational and estimation purposes only. It does not provide financial, mortgage, tax, investment, or legal advice. Actual rates, payments, taxes, fees, insurance costs, eligibility, and loan terms vary by lender, location, credit profile, and market conditions. Always compare official offers and consult a qualified professional before making financial decisions.

Last updated June 2026 · Prepared by the mCalculator Editorial Team