Calculate your monthly car payment and total vehicle cost
Enter the vehicle price, down payment/trade-in value, interest rate and loan term. The calculator shows your monthly car payment, total amount financed, total interest, and the full cost of the vehicle — including any sales tax and fees if you add them. Drag the sliders to see how a longer term lowers the payment but raises total interest.
Shorter terms save interest but mean higher monthly payments. 60 months is the sweet spot.
Car payments use the same amortization formula as mortgages: M = P × [r(1+r)^n] / [(1+r)^n − 1], where P is the amount financed, r is the monthly interest rate, and n is the number of monthly payments. A longer term reduces the payment but increases the total interest paid.
Financing $32,950 at 6.5% produces a monthly payment of $645 and total interest of $5,732 over the term. Shaving 12 months off the term would raise the payment but save thousands in interest — the trade-off this calculator makes visible instantly.
A common rule of thumb is that your total monthly transportation costs (car payment, insurance, gas, maintenance) should not exceed 15-20% of your monthly take-home pay. If your car payment alone is more than 10% of your take-home, you're likely stretching too thin.
New cars typically qualify for lower interest rates than used cars because they're less risky for lenders. As of 2026, average rates are around 6-7% for new cars and 7-9% for used cars, depending on your credit. New cars also qualify for manufacturer 0% APR deals sometimes.
Dealer doc (documentation) fees are charges for preparing the sales paperwork. They vary by state and dealer — typically $100-$800. Some states cap the maximum doc fee, while others don't. These fees are often negotiable, or at least worth asking the dealer to waive or reduce.
Being upside down (or underwater) means you owe more on your car loan than the car is actually worth. This happens easily with long-term loans on new cars, which depreciate quickly. It's risky because if you total the car, insurance only pays the actual cash value — you'd still owe the difference. GAP insurance covers this gap.
Longer loans (72 or 84 months) give you lower monthly payments but you pay much more interest overall, and you're much more likely to end up upside down. They also keep you in debt longer. Most financial advisors recommend keeping your auto loan to 60 months or less if possible.