Work out a real car payment before you walk into the dealership. Enter the price, down payment, trade-in, sales tax, and fees and the calculator shows the amount financed, monthly payment, total interest, and total cost — including any negative equity rolled in from your current car — plus a side-by-side of 36 to 84-month terms so the cost of stretching the loan is obvious.
For other borrowing, the loan calculator can solve for a rate or term and the mortgage calculator covers home loans with taxes and PMI. If you want to know the sales tax on its own, the sales tax calculator adds or backs it out of any price, and the compound interest calculator shows what the same monthly amount could grow to if saved instead.
Tempted by a 72- or 84-month term? Read why a longer car loan costs more — a worked 48 vs 60 vs 72 vs 84-month comparison, negative equity, and the levers that beat stretching the term.
Frequently asked questions
How is the amount financed on a car loan calculated?
Start with the negotiated vehicle price, add sales tax and any fees you are rolling into the loan (title, registration, documentation, add-ons), then subtract your cash down payment and your trade-in equity. Trade-in equity is the trade-in value minus whatever you still owe on that vehicle. If the result is positive it lowers the loan; if you owe more than the car is worth, the difference is negative equity and it gets added to the new loan. The monthly payment is then calculated on that amount financed using the standard amortization formula at your rate and term.
Is sales tax charged on the full price or after the trade-in?
It depends on your state. Most US states let you subtract the trade-in value before calculating sales tax, which can save hundreds of dollars, and that is this calculator's default. A handful — including California, Hawaii, Kentucky, Maryland, Virginia, and Washington, D.C. — tax the full price regardless of a trade-in, and some states have caps or special rules. Switch the tax basis option to match where you register the car. Rules change, so confirm with your state's DMV or revenue department, and remember local taxes may add to the state rate.
What is negative equity and why is it risky?
Negative equity means you owe more on your current car than it is worth as a trade-in. Dealers can roll that shortfall into your new loan, but you then pay interest on debt for a car you no longer own, and the new loan starts out underwater too, since new cars lose value quickly. That makes it harder to sell or trade later and raises the loss if the car is totaled. The calculator shows exactly how much negative equity is being added and includes it in the total cost. Paying it down in cash, choosing a cheaper car, or waiting can break the cycle.
Is a 72- or 84-month car loan a good idea?
Longer terms lower the monthly payment, but you pay more total interest, lenders often charge a higher rate for longer terms, and you are more likely to owe more than the car is worth for years. The comparison table under the result shows the payment and total interest for 36 to 84 months on the same amount, so you can see the trade-off directly. A common guideline is to keep auto loans to 60 months or less and to choose a car whose payment fits that term. If only the longest term is affordable, the car may be more than the budget supports.
Should I use the dealer's APR or my bank's rate?
Use whichever rate you will actually get, and compare both. Getting preapproved by a bank or credit union before visiting the dealer gives you a baseline; dealers can sometimes beat it, especially with manufacturer promotional rates like 0% or 1.9%. Those promotions may require giving up a cash rebate, so run both scenarios: the promo rate with no rebate, and your bank rate with the rebate entered as extra down payment. Whichever gives the lower total cost is the better deal. Watch for add-ons folded into the amount financed, which raise the payment without changing the rate.