Auto Loan Refinance Break-Even Calculator

US auto loan planning tool

Auto Loan Refinance Break-Even Calculator

Compare your current car loan with a refinance offer. See monthly payment changes, true interest savings after fees, when refinancing pays for itself, and the balance you might owe if you sell or trade in the car.

1. Your current auto loan

Use the remaining principal and scheduled months left, not the original loan amount and term. Check your lender for an up-to-date payoff quote.

Remaining loan principal ($) Principal still owed on your current loan.

Current annual interest rate (%) Interest rate used for amortization, not a fee-inclusive APR.

Current loan months remaining Enter the remaining scheduled payments.

2. The refinancing offer

Enter the new interest rate, term and costs. Longer terms can lower the monthly bill while increasing total interest.

New annual interest rate (%) Use the note rate; do not double-count finance charges already included in a disclosed APR.

New loan term (months) For a fair term comparison, start with the same number of remaining months.

Lender and origination fees ($) Enter refinancing fees not already included elsewhere.

Title, registration and other fees ($) Include only actual additional refinancing costs.

Old loan prepayment penalty ($) Confirm with your lender and state law. Paid upfront in this model.

How will new-loan fees be paid? Prepayment penalty is modeled as cash upfront either way. Financing must be allowed by the lender.

Expected months before selling or trading in 0 means selling immediately. Calculations compare payoff at this future month.

Interest rate vs. APR: These payment formulas use the contractual interest rate. The disclosed APR may also incorporate mandatory fees. If you enter that fee-inclusive APR and add those fees again, the estimate may double-count costs. CFPB explanation.

Your auto refinance comparison

Change in monthly payment — First scheduled payment difference

Lifetime interest and fee savings — If both loans run to scheduled payoff

Lasting refinance break-even — Interest savings fully offset fees

Net financing savings at sale date — At planned sale/trade-in month

Keep your current loan

Remaining loan principal—

Estimated monthly payment—

Remaining lifetime interest—

Remaining total payments—

Scheduled payoff—

Refinance the loan

New principal, including financed fees—

Estimated monthly payment—

Remaining lifetime interest—

Refinance fees and prepayment penalty—

Total payments plus upfront costs—

Scheduled payoff—

If you sell or trade in the vehicle

A smaller payment is not always a lower borrowing cost. This comparison includes payments made, fees and the remaining balance you would need to settle at that date.

Time from now—

Current loan payoff balance—

New loan payoff balance—

Difference in payoff balances—

Current loan interest accrued by sale—

Refinance interest accrued by sale—

All refinance fees—

Net financing-cost difference—

Remaining loan balance over time

This chart shows how a different interest rate or loan term affects the balance owed, even when your monthly payment falls.

Current loan Refinanced loan Planned sale

What if you choose a different refinance term?

Compare shorter and longer terms at the same offered interest rate. Actual lenders may quote a different rate for each term.

Refinancing loan term and total borrowing cost comparison
Refinance term	Monthly payment	Refinance interest	Net lifetime savings

Payment and balance schedule

Key months and payoff milestones are shown. Export the full month-by-month schedule for a closer review.

Monthly debt and cost comparison
Month	Old loan payment	Old balance	New loan payment	New balance	Net financing savings

How the auto refinance break-even calculation works

Monthly payment is calculated using a standard fixed-rate amortization formula: P × r ÷ [1 − (1 + r)⁻ⁿ], where P is the loan principal, r is the annual interest rate divided by 12, and n is months remaining. At 0% interest, payment equals principal ÷ months. The new loan may include eligible fees in the principal.

Lifetime savings = interest remaining on current loan − interest on refinanced loan − refinancing fees − old loan prepayment penalty. This captures the full financing expense rather than treating lower monthly payments as an automatic saving.

At a planned sale date, net financing savings use cumulative old interest minus cumulative new interest minus total refinancing costs. This is mathematically equivalent to comparing all payments already made plus the loan payoff balances at that date, including cash fees. The lasting break-even month is the earliest point at which this net figure is nonnegative and stays nonnegative through both loans’ projected payoffs.

Scope: These calculations use level monthly payments and monthly interest, not the daily simple-interest calculations used by many auto lenders. They omit payoff-quote timing differences, taxes, loan add-ons, cash-out refinancing, credit score changes and vehicle depreciation. Confirm the official lender payoff quote and Truth in Lending disclosures; the interest rate here is not an independently computed disclosed APR.

Frequently asked questions

When does refinancing a car loan break even?

It breaks even in financing-cost terms once interest avoided covers the total refinancing fees and any prepayment penalty. If you extend the term, you may temporarily save on interest before a longer repayment period makes the new loan more expensive later, so the calculator also checks whether savings last through payoff.

Can a lower monthly payment cost more overall?

Yes. Extending the new loan term can mean more payments and more total interest, even with a lower interest rate. Check lifetime costs and the balance you will owe if you trade in the car.

Does refinancing trigger a prepayment penalty?

Your existing contract and applicable state law determine this. CFPB recommends checking the current loan contract and Truth in Lending disclosure for any penalty before refinancing.

Should I finance refinance fees into the new loan?

Financing eligible fees avoids some upfront cash but raises the amount borrowed and usually adds interest on those fees. The lender must allow it; compare both fee payment options.

Is APR the same as the interest rate?

No. The APR generally includes the cost of interest and certain mandatory loan fees, whereas the contractual interest rate determines interest accrual. The calculator asks for the interest rate and adds fees separately.

What if I plan to sell the car before paying off the new loan?

Enter the expected months until sale. The comparison accounts for the unpaid loan balances and financing costs accumulated through that month. It does not predict the car’s market value or whether you will have negative equity.

Does this calculate exact lender payoffs?

No. Actual loans may accrue daily interest, and a payoff quote can include interest and charges not reflected in your displayed principal. Confirm balances, fees, rates and payoff dates with your lenders.

Official sources: CFPB: comparing auto loans; CFPB: prepayment penalties; CFPB: auto loan interest methods. Disclaimer: Educational estimates only, not credit, legal, tax or lending advice. Actual loan disclosures and written payoff quotes control.