ac AutomotiveCalc
Ownership costs

Auto Refinance Calculator

Compare keeping your current car loan with refinancing, including fees, monthly payment changes, and total remaining cost.

By AutomotiveCalc · Published September 9, 2026 · Method & standards

Your numbers

Example calculation

Example results are shown below. Controls become available when the calculator loads.

Use the remaining principal and remaining months, not the original loan amount and term. Enter contract interest rates. Include fees or payoff adjustments once, either financed or paid upfront.

Current loan
Current loan
Proposed refinance
Proposed refinance
Total remaining savings after costs$692.01
Monthly payment reduction$27.56
Current estimated payment$635.99
New estimated payment$608.44

Refinancing has a lower modeled total remaining cost after the entered fees.

Costs from today until each loan ends
MeasureKeep loanRefinance
Months remaining3636
Starting balance$20,000.00$20,000.00
Remaining interest$2,895.81$1,903.79
Upfront refinancing costs$0.00$300.00
Total remaining payments and upfront costs$22,895.81$22,203.79

Negative savings mean higher cost. Financed fees are included in the new starting balance and earn interest; they are not added again to the total.

Calculated on your device. No account needed. Report a problem

How to use this calculator

Replace the example values with your own measurements or specifications. Keep the units shown beside each label. Results update as you type; reset restores the example.

Both options assume fixed rates, equal monthly periods, on-time payments, and full repayment without a balloon. Past payments and interest are excluded because they cannot be changed by refinancing. This is an undiscounted cash-total comparison, not a net-present-value calculation. Daily interest, lender rounding, variable rates, extra payments, and early sale or payoff are not modeled.

The formula

Calculate each fixed monthly payment as P × r ÷ [1 − (1 + r)⁻ⁿ], with r = annual rate ÷ 1,200; at 0%, use P ÷ n. New principal = current balance + financed costs. Total savings = current remaining loan payments − new loan payments − upfront refinancing costs. Monthly reduction = current payment − new payment.

A worked example

For a $20,000 balance with 36 months remaining at 9%, the modeled payment is $635.99. Refinancing the same balance for 36 months at 6% gives $608.44. With $300 paid upfront and no financed fees, total remaining savings are about $692.01. Rates and fees here are examples, not offers.

Common questions

Can a lower payment still cost more overall?

Yes. Extending repayment can reduce the monthly payment while increasing total interest. The first result includes remaining payments and entered refinancing costs, so compare it with the monthly reduction.

Where do I enter origination fees or prepayment costs?

Enter each cost once: in costs added to the new loan if financed, or costs paid upfront if paid separately. Include any applicable payoff adjustment. Confirm the lender’s payoff quote and contract; do not add a fee again if it is already included elsewhere.

Should I use the original loan amount?

No. Use the current principal balance and the months still remaining. If the calculated current payment differs materially from your contract payment, this simplified remaining-balance model may not represent your loan.

Does this use APR?

Use the contract interest rate. APR may include fees; substituting it while also entering fees can misstate costs. This tool does not calculate a legal disclosure APR.

Does the calculator recommend a lender or guarantee approval?

No. It compares the numbers you enter. It does not check eligibility, credit terms, vehicle value, or whether a lender offers the proposed rate.

Can I use this if I will sell the car before the loan ends?

The result assumes both loans run to their respective ends. An earlier sale or payoff requires comparing payments made, remaining payoff balances, and applicable costs at that date.

Sources & calculation method

Related guidance: CFPB: comparing auto-loan offers. Accessed September 9, 2026. The equation above describes this tool’s model; the reference provides practical context and does not endorse this site.

Prepared with AI assistance. Formula examples and input validation have automated checks. This page has not received an independent automotive professional review. Read our review standards.