Calculate your car loan payment with sales tax, fees, rebates and a trade-in — including negative equity when you owe more than the trade is worth.
Enter what the dealer allows for your car AND what you still owe on it — the difference is what actually comes off the new loan.
Most states charge sales tax on the price minus your trade-in allowance, but a number of them tax the full price. Check your state's rule — on a $10,000 trade at 7% the difference is $700.
Estimates for planning only, not a loan offer or financial advice. Sales tax rules, dealer fees and lender terms vary by state and by lender — your actual payment comes from the contract you sign.
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A car payment is not just price divided by months. Sales tax, title and registration, a rebate, and whatever is left on the loan you are trading in all land in the same number. This calculator takes each of them separately, shows the arithmetic line by line, and tells you what the deal costs in total — not just per month.
A car loan is a secured, amortising loan: the car is collateral, and every payment splits between interest on the outstanding balance and principal that reduces it. Early payments are mostly interest and late ones mostly principal, which is why stretching the term raises the total cost even though it lowers the monthly figure. What you finance is the out-the-door price — vehicle price plus sales tax and fees, less any rebate — minus your cash down and the net value of your trade-in.
Monthly payment formula
Know the payment your own numbers produce, so the finance office is confirming your figure rather than setting it.
If the dealer's monthly figure is higher than yours, the difference is almost always fees, a longer term, or a trade-in payoff you had not counted.
See what rolling the remaining balance forward actually adds, and compare it against paying the old loan down first.
Compare 36 through 84 months on the same amount financed and see the extra interest each step costs.
Most calculators ask only what your trade-in is worth. If you still owe more than that, the shortfall rolls into the new loan — and this shows exactly what that costs per month and in total interest, against the same deal with the trade paid off.
Most states charge tax on the price after the trade-in allowance; several tax the full price. That single switch is worth $700 on a $10,000 trade at 7%, so it is a control rather than a hidden assumption.
Title, registration and documentation fees are entered separately, and you choose whether they are rolled into the loan or paid at signing. Either way the breakdown column adds up to the amount financed.
The worked derivation prints each equation with the numbers substituted in, so you can verify the payment by hand instead of trusting a black box.
The dealership sells you a monthly payment. The calculator shows total interest, total cost to drive away, and how much more a 72- or 84-month term really costs than a 48-month one.
Use M = P × [r(1+r)ⁿ] / [(1+r)ⁿ − 1], where P is the amount financed, r is the APR divided by 12, and n is the number of months. On $32,950 financed at 6.5% over 60 months, r is 0.0054167 and the payment is $644.71. The amount financed is the out-the-door price minus your down payment and net trade-in — not the sticker price.
The shortfall — the negative equity — is added to the new loan. On a $12,000 trade with $18,000 still owed, $6,000 rolls forward. Financed at 8.49% over 72 months that adds about $106 a month and roughly $1,600 in extra interest, and it puts you underwater on the new car from day one.
In most states, yes: the tax is charged on the price minus the trade-in allowance, so a $10,000 trade at a 7% rate saves $700. A number of states tax the full purchase price instead. The rule is set by your state, so this calculator asks rather than assumes — check your state's department of revenue before relying on either figure.
Rolling them in keeps cash in your pocket but you pay interest on them for the whole term. On $2,950 of tax and fees at 6.5% over 60 months, financing them costs about $520 in interest. Paying them at signing avoids that entirely, and also keeps the loan smaller relative to the car's value.
It lowers the payment and raises the cost. Financing $32,950 at 6.5%, a 48-month term costs $4,468 in interest and an 84-month term costs $8,046 — about $3,578 more for the same car. Longer terms also keep you underwater for longer, because the balance falls more slowly than the car depreciates.
Usually not. Most states tax the price before a manufacturer rebate is applied, treating the rebate as a payment rather than a discount. A dealer discount, by contrast, normally does reduce the taxable price. This calculator subtracts the rebate from what you finance but leaves the taxable amount alone.
Enough to keep the loan below the car's value. A new car loses a large share of its value in the first year, so financing the full out-the-door price with nothing down usually means owing more than the car is worth for the first year or two. Watch the loan-to-value figure: under 100% means the loan is covered by the car.
Almost always one of four things: documentation and registration fees you had not included, sales tax charged on the full price rather than after the trade-in, a payoff on your trade that exceeds its allowance, or a term or APR different from the one you assumed. Enter each of them separately here and the two figures should reconcile.