Auto Finance Calculator
Model the monthly payment on a financed purchase or a lease. Figures are estimates — the rate you actually qualify for depends on your credit profile and the program attached to the specific vehicle.
A dealership can quietly add margin to the rate your lender approved — the industry calls it dealer reserve. On a $40,000 loan over 60 months, a single point of markup means roughly $1,000 of extra interest. Before you sign, our advisors check the quoted rate against your actual buy rate.
Consult an Advisor →Understanding the Inputs
Five numbers drive the payment on nearly every retail car deal. This tool lets you adjust each one and watch the effect.
Vehicle Price is the agreed selling price before tax, title, and government charges — not the sticker. For the tightest estimate, take your out-the-door figure and strip out taxes and government fees.
Down Payment is the cash you bring to signing. Trade-in equity has its own line, so leave it out here.
Trade-In Value is what the dealer will pay for the car you already own. Their opening number is almost never their ceiling — the car's wholesale value at auction sets the realistic floor on what they can reasonably pay.
Interest Rate (APR) is the rate your lender approved. No variable gets padded more often in the F&I office: the dealer may layer additional margin — typically up to two percent — onto your approved rate with no duty to disclose it. That added spread is booked as dealer reserve income.
Loan Term is how many months the financing runs. Stretching it shrinks the monthly payment while raising the total interest you pay.
The results show your estimated monthly payment, the interest paid across the full term, and what the vehicle ultimately costs once that interest is folded in.
A Worked Example — The Real Price of a 1.5% Rate Markup
Take a $42,000 vehicle with $5,000 down, $3,000 of trade-in credit, a 6.9% APR, and a 60-month term. That leaves $34,000 financed, an estimated monthly payment near $672, and roughly $6,332 in interest over the life of the loan.
Now suppose the buyer was actually approved at 5.4% and the dealer quoted 6.9% — a 1.5% rate reserve. At the true approved rate, the identical loan runs about $648 a month with roughly $4,892 in total interest.
That 1.5% spread costs the buyer $24 every month — $1,440 across the loan. None of it is lender profit. The lender pays it back to the dealership as reserve income generated by the padded rate.
No F&I markup is more common. It's entirely legal — and almost never mentioned at the desk. Before you sign, our advisory confirms the rate the dealer is quoting against the buy rate you were actually approved for.
Common Questions from Buyers
Is the interest rate the dealer quotes the same rate my lender approved?
Often it isn't. A dealership may add as much as two percentage points — occasionally more — on top of the rate the lender actually approved, with no obligation to tell you. That spread, known in the industry as dealer reserve, is one of the most routine finance-office markups and also one of the simplest to catch when you have the right paperwork to check it against.
How is a money factor different from an APR?
APR is the rate on a financed purchase; leases use a money factor instead. Multiply the money factor by 2,400 to get its rough APR equivalent — 0.00288, for instance, works out to roughly 6.9%. Lease quotes usually show the money factor rather than the APR, partly because the same cost of borrowing looks much smaller written that way.
Will stretching out the loan term save me money?
It lowers the payment, not the cost. Financing the same balance over 72 months instead of 60 can add several thousand dollars of interest by the time the loan is paid off. Most shoppers fixate on the monthly figure, but the number that actually decides whether the longer term is worth it is the total you pay over the full term.
Are sales tax and fees included in these results?
They are not. Sales tax, title and registration charges, and dealer documentation fees differ by state and by dealer, so this tool models only the financing side of the transaction. For a complete out-the-door figure built around your taxes, fees, and deal structure, request a consultation.
Disclaimer: The figures produced here are illustrative and educational only — they are not a financing offer, commitment, or guarantee. Your actual payment will depend on your credit profile, available lender programs, applicable taxes and fees, and the specifics of your transaction. Meridian Auto Advisory is not a lender, a dealership, or a financial advisor. Confirm your rate and terms directly with your lender before you sign anything.