Auto Loan Calculator

What actually gets financed

Amount financed = vehicle price − cash down payment − trade-in value + sales tax + fees.

Interest is then charged on that whole amount, so financed fees and taxes cost more than their face value. A $500 documentation fee financed over 72 months at 7.5% costs about $622 by the time the loan ends.

Because the tax and fees ride inside the balance that is amortized, the financed amount can end up several thousand dollars above the price on the window sticker. That is why two buyers at the same listed price can be paying noticeably different monthly payments - the cash due at signing and the deal’s add-ons decide as much as the sticker does.

The term trap

The payment formula spreads the balance over more months, so a longer term reduces the payment and increases the interest. On a $30,000 loan at 7.5%, moving from 48 to 72 months cuts the payment by roughly $207 but adds about $2,530 of interest.

Longer terms also keep you underwater on the car for longer, because depreciation outpaces the loan balance for the first few years. The longer the term, the more months you carry a loan bigger than the car is worth, which matters the moment you need to sell or trade in before that gap closes.

The term is not just a monthly-payment dial. At the far end of the options on this page, a seven-year loan can save hundreds of dollars a month next to a two-year term while quietly adding thousands in interest - the exact trade this calculator is built to make visible.

Tax and fee conventions

Sales tax treatment varies: some states charge tax on the full price, others credit the trade-in, and a few charge a separate vehicle tax. Dealer documentation fees, title, registration and any extended warranty get financed unless you pay them at signing. Adjust both fields to match your state and your paperwork.

The default here credits the trade-in before tax because that is the rule in most states, but it is worth confirming against your own paperwork before the number feels wrong. The trade-in is also an input you control: negotiating a higher trade-in value saves tax as well as cash, since a larger credit shrinks the taxable amount the same way a larger down payment does.

Negative equity, and the way out

New-car financing usually opens inside a negative-equity gap: because depreciation outruns the loan balance for the first few years, the amount you owe can exceed what the car is worth for much of the term. The tax and fee conventions that built the financed amount above make that gap deeper, because financed tax and fees become part of the balance that must depreciate away.

Early payoff is the lever that closes the gap from the end. A simple-interest auto loan generally carries no prepayment penalty, so the remaining unearned interest is saved and the schedule shortens; whether a penalty exists is a contract detail, so the financing agreement is the document to check before paying early. The amortization table on this page is the honest view of how many months the loan still has to run.

Turning the payment into a decision

The monthly payment is the number the deal is negotiated on, but the figure that decides whether it was a good deal is the total of payments: principal, sales tax, financed fees and interest, added up over the whole term. Two offers with the same payment can differ by thousands once the term and the APR are put back side by side.

Work the deal in the order the money actually moves. Agree the vehicle price first, then the trade-in value, then the financing; negotiating all three at once is how a lower payment gets paid for with a longer term or a thinner trade-in allowance. The fields here are separated for that reason - each one is a different conversation, and each one moves the interest bill differently.

Before signing, ask the finance office for the total of payments and the APR in writing. A payment you can afford on a term that outlives the car is exactly the shape of deal this page is built to expose.