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Auto Loan Refinance Calculator

Compare your current auto loan to a refinance offer: new payment, monthly savings, break-even months on fees, and total interest remaining vs. a new loan. See when a lower APR actually saves money.

What this calculator is for

An auto loan refinance calculator compares your current note to a new APR and term: payment drop, total interest remaining, and how many months of savings pay back refinance fees. Refinancing only wins if you keep the loan long enough to pass break-even.

Credit unions, online lenders, and captive refi offers spike when rates move. Use this when your score improved, when you want to drop PMI on a non-auto product, or when a dealer put you on a high APR and you can exit after a few on-time payments.

A good outcome: you know break-even months on fees and whether a longer new term trades a lower payment for more total interest — a common trap.

Calculator

How to use this calculator

  1. Enter current balance, APR, and months remaining on your existing loan.
  2. Enter the refinance APR, new term, and fees from the lender.
  3. Choose whether fees are paid upfront or rolled into the new balance — compare monthly savings and total interest.

Enter months remaining, not original 60-month term, on the current loan.

Fees paid upfront vs rolled in change the principal — model both if your lender offers either.

If you are close to payoff, refi often does not pay — break-even may exceed months left.

The math: do it without a calculator

Payment = P × [r(1+r)n] ÷ [(1+r)n − 1]

Monthly savings = Current payment − New payment

Break-even (months) = Refinance fees ÷ Monthly savings

A longer new term can lower the payment but increase total interest — always read both payment and total interest.

Break-even months = refinance fees ÷ monthly savings (when savings > 0).

Total interest comparison uses remaining payments on old loan vs full new schedule — extending term can raise total interest even when payment falls.

Real-world examples

Credit union refi from dealer 9.9%

Balance $21,000, 42 months left at 9.9% vs refi at 5.9% for 48 months with $399 fee rolled in. Monthly savings near $45–$55 can break even on fees in 7–9 months — but extending term may still add total interest.

Troubleshooting & fine-tuning your setup

Refinance Savings Not Showing Up in Real Life

If monthly payment dropped but you feel poorer, you may have extended the term — total interest can rise even when payment falls. Check total interest remaining in the comparison.

Fees rolled into the loan cost interest for years. Break-even months only matter if you keep the loan past that point.

Frequently asked questions

Auto Refinance FAQs

When does refinancing a car loan make sense?

When you can drop APR meaningfully, keep similar or shorter term, and stay in the loan past fee break-even — often after credit improves or rates fall.

Will refinancing hurt my credit?

A hard inquiry and new account may dip scores briefly; multiple auto inquiries within a 14–45 day shopping window often count as one for scoring models.

Can I refinance if I am underwater?

Some lenders allow high LTV refi; many do not. You may need cash down to cover the gap.

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