Car Loan Refinance Calculator

Live keep-term vs stretch refinance board with an APR gap peel and fee soak for cash or rolled fees, so a lower payment is not confused with a true interest win.

Educational planning only. Not a lender quote, credit decision, pre-approval, or advice to refinance. Confirm offers with written disclosures; LTV, vehicle age, and credit tier can change eligibility.

By Ahmet C. Toplutaş·Site owner & editor · Finance tools

Last updated May 21, 2026 · Reviewed May 21, 2026 · Planning estimates only - not tax, medical, or investment advice

Keep remaining term vs stretch

A refinance offer is two decisions glued together: a new APR and a new term. Keep-term holds your remaining months so you see the rate cut alone. Stretch uses the term on the offer, which often resets the clock longer and can lower the payment while raising total interest.

This page's framing is a keep-term vs stretch twin, with an APR gap peel and a fee soak for cash vs rolled fees. It is not a lease depreciation/rent board, not an auto-loan equity race, and not a CAC recovery clock.

Decision framing: “If I only changed the rate, what happens, and what does stretching the term do to payment versus total interest?”

Educational planning only. Not a lender quote, credit decision, pre-approval, or advice to refinance. Vehicle age, LTV, and credit tier can block offers this sketch cannot see. See our disclaimers.

APR gap peel

The gap is current APR minus new APR in percentage points. A two-point cut on a short remaining term saves less total interest than the same cut early in a long loan. The peel sits beside both paths so you do not confuse a marketing “lower rate” headline with the dollars that actually move.

Tip: use Match keep-term to set the new term equal to months left, then only change APR and fees. That is the cleanest rate-only comparison.

Fee soak: cash vs rolled

Refinance fees matter as much as the rate. Cash fees leave principal alone; monthly payment savings must cover them (fee soak months = fees ÷ monthly payment drop). Rolled fees raise the financed balance, so you pay interest on the fees themselves.

If the payment does not fall, cash fees never soak from payment savings on this board. That is a hard stop signal even when the new APR looks attractive.

The term-reset trap

Stretching from, say, 36 months left to a fresh 60-month term can cut the payment while increasing lifetime interest versus simply staying. When the stretch path shows a payment drop and a negative interest delta, you are buying payment relief with a longer clock.

That tradeoff can still be rational for cashflow, but it is not the same as “saving money on the loan.” Read net vs stay on both cards before calling the offer a win.

Core relations

Payments use the standard amortizing formula. Interest over a path is total payments minus the financed balance. Net vs stay subtracts cash fees from interest savings when fees are paid upfront.

Payment = B × r(1+r)^n / ((1+r)^n − 1) r = APR/100/12 · n = months Interest = payment × n − financed balance Fee soak (cash) = fees ÷ monthly payment drop

Example keep-term: $20,000 left, 7.5% → 5.5%, 48 months, $500 cash fees. Payment falls and interest savings usually clear fees if you keep the term. Stretch the same balance to 60 months and re-check interest delta before celebrating the lower payment.

Where this hands off

Sibling boards for payments, equity, lease alternatives, and amortization detail.

Auto loan (payment and equity race literacy)
Amortization (month-by-month interest/principal)
Car lease (if you are comparing lease vs loan paths)
Car affordability / depreciation
Terms: finance glossary

Worked scenarios

Scenario A: Keep-term cut. $20k balance, 7.5% → 5.5%, 48 months both sides, $500 cash fees. Keep and stretch cards match; fee soak should clear well inside two years if the payment drops.

Load Stretch trap. Months left 36, new term 60, modest APR cut. Payment falls, but interest vs stay can flip negative. That is the term-reset warning on the board.

Scenario B: Fees rolled. $900 fees into principal at a keep-term rate cut. Financed balance rises; there is no cash soak bar. Compare interest on the higher principal to staying put.

Scenario C: Big APR gap. 8.9% → 6.4% with keep-term and modest fees. Strong rate cut often dominates small fees; still read soak months if you might sell the car soon.

Scenario D: Short horizon. If you expect to sell in under a year, a slow fee soak can erase the paper interest win even when keep-term looks fine on a full-term view.

Common mistakes

Judging only by the new monthly payment.
Ignoring whether fees are cash or rolled into principal.
Resetting to 60 or 72 months without reading interest vs stay.
Using APR quotes that exclude lender fees already modeled here separately.
Skipping equity / underwater checks when the car has lost value.

How to use this board

Enter balance, current APR, months left, new APR, new term, and fees.
Choose fees cash or rolled; optionally Match keep-term.
Compare keep vs stretch cards and the APR gap peel.
Read fee soak on the active path. Share writes query params; typing does not rewrite the address bar.

When not to stop at this sketch

Stop here to compare rate-only keep-term against a stretch offer and to see how fees soak. Hand off for amortization detail, equity vs depreciation, or a fresh payment from scratch. For binding decisions, use written lender disclosures.

Payment schedule: amortization calculator.
Loan vs value: auto loan calculator.
Lease alternative: car lease calculator.

Frequently asked questions

How does this car loan refinance calculator work?

It compares staying on your current loan to refinancing at a new APR. A keep-term path matches your remaining months; a stretch path uses the new term you enter. An APR gap peel shows the rate cut, and a fee soak shows how long monthly payment savings take to cover cash fees (or how rolled fees raise the financed balance).

What is the keep-term vs stretch twin?

Keep-term refinances at the new APR but keeps your remaining months so you isolate the rate effect. Stretch resets the term (often longer), which can lower the payment while adding months of interest. Comparing both reveals the term-reset trap.

What is the term-reset trap?

A longer new term can cut the monthly payment even when the rate improvement is small, while total interest paid rises. If payment drops but interest delta is negative versus staying, you are stretching the clock more than you are saving on rate.

Cash fees vs fees rolled into the loan?

Cash fees leave the principal unchanged and must be soaked by monthly payment savings. Rolled fees increase the financed balance, so interest is charged on the fees too. Pick the mode that matches your offer.

What is fee soak?

For cash fees, fee soak months equal fees divided by the monthly payment reduction. If the payment does not fall, cash fees never soak from payment savings on this sketch.

Does this include taxes, warranties, or credit-tier pricing?

No. It is a payment and interest literacy board for balance, APR, term, and fees. Lender quotes, LTV limits, vehicle age rules, and add-ons can change the real deal.

Is this a recommendation to refinance?

No. It is educational planning only, not a lender quote, credit decision, or personalized financial advice. Confirm numbers with your lender and a qualified adviser when stakes are high.

Sources

Loading…

Methodology & sources

Our finance calculators use standard formulas and common assumptions. Results are estimates and may differ due to fees, taxes, rounding, and lender/provider policies. Use this for planning—not as a quote.

Core sources

Loans hub Finance formulas Editorial policy Corrections Contact

Disclosure & resources

Car Loan Refinance Calculator: Savings Analysis results are estimates for planning—not quotes from lenders or tax authorities. Some links below are educational (government or nonprofit). If we add partner offers later, they will be labeled and this page will note any compensation.

Disclaimers · Editorial policy · Finance resources hub

Keep remaining term vs stretch

Decision framing: “If I only changed the rate, what happens, and what does stretching the term do to payment versus total interest?”

Educational planning only. Not a lender quote, credit decision, pre-approval, or advice to refinance. Vehicle age, LTV, and credit tier can block offers this sketch cannot see. See our disclaimers.

APR gap peel

Tip: use Match keep-term to set the new term equal to months left, then only change APR and fees. That is the cleanest rate-only comparison.

Fee soak: cash vs rolled

If the payment does not fall, cash fees never soak from payment savings on this board. That is a hard stop signal even when the new APR looks attractive.

The term-reset trap

That tradeoff can still be rational for cashflow, but it is not the same as “saving money on the loan.” Read net vs stay on both cards before calling the offer a win.

Core relations

Payments use the standard amortizing formula. Interest over a path is total payments minus the financed balance. Net vs stay subtracts cash fees from interest savings when fees are paid upfront.

Payment = B × r(1+r)^n / ((1+r)^n − 1) r = APR/100/12 · n = months Interest = payment × n − financed balance Fee soak (cash) = fees ÷ monthly payment drop

Worked scenarios

Scenario A: Keep-term cut. $20k balance, 7.5% → 5.5%, 48 months both sides, $500 cash fees. Keep and stretch cards match; fee soak should clear well inside two years if the payment drops.

Load Stretch trap. Months left 36, new term 60, modest APR cut. Payment falls, but interest vs stay can flip negative. That is the term-reset warning on the board.

Scenario B: Fees rolled. $900 fees into principal at a keep-term rate cut. Financed balance rises; there is no cash soak bar. Compare interest on the higher principal to staying put.

Scenario C: Big APR gap. 8.9% → 6.4% with keep-term and modest fees. Strong rate cut often dominates small fees; still read soak months if you might sell the car soon.

Scenario D: Short horizon. If you expect to sell in under a year, a slow fee soak can erase the paper interest win even when keep-term looks fine on a full-term view.

When not to stop at this sketch

Payment schedule: amortization calculator.
Loan vs value: auto loan calculator.
Lease alternative: car lease calculator.

Frequently asked questions

How does this car loan refinance calculator work?

What is the keep-term vs stretch twin?

What is the term-reset trap?

Cash fees vs fees rolled into the loan?

What is fee soak?

For cash fees, fee soak months equal fees divided by the monthly payment reduction. If the payment does not fall, cash fees never soak from payment savings on this sketch.

Does this include taxes, warranties, or credit-tier pricing?

No. It is a payment and interest literacy board for balance, APR, term, and fees. Lender quotes, LTV limits, vehicle age rules, and add-ons can change the real deal.

Is this a recommendation to refinance?

No. It is educational planning only, not a lender quote, credit decision, or personalized financial advice. Confirm numbers with your lender and a qualified adviser when stakes are high.

Keep remaining term vs stretch

APR gap peel

Fee soak: cash vs rolled

The term-reset trap

Core relations

Where this hands off

Worked scenarios

Common mistakes

How to use this board

When not to stop at this sketch

Frequently asked questions

How does this car loan refinance calculator work?

What is the keep-term vs stretch twin?

What is the term-reset trap?

Cash fees vs fees rolled into the loan?

What is fee soak?

Does this include taxes, warranties, or credit-tier pricing?

Is this a recommendation to refinance?

Sources

Methodology & sources

Disclosure & resources

Keep remaining term vs stretch

APR gap peel

Fee soak: cash vs rolled

The term-reset trap

Core relations

Where this hands off

Worked scenarios

Common mistakes

How to use this board

When not to stop at this sketch

Frequently asked questions

How does this car loan refinance calculator work?

What is the keep-term vs stretch twin?

What is the term-reset trap?

Cash fees vs fees rolled into the loan?

What is fee soak?

Does this include taxes, warranties, or credit-tier pricing?

Is this a recommendation to refinance?

Sources

What this number means

Share your calculation