A car payment is easy to negotiate and easy to misunderstand. Stretch the term and the monthly number drops. The amount you pay for the privilege of borrowing usually rises, and you can owe more than the car is worth while you are still driving it.
What actually gets financed
The amount financed is the price, plus sales tax and fees, minus cash down and the trade-in. This calculator taxes the price after the trade-in, which is how many states handle a vehicle purchase. A payment quoted before tax, fees, and the trade-in are settled is not the payment you will sign.
The APR is the cost of borrowing. A rate that looks ordinary on a large balance still produces thousands of dollars of interest over five or six years. Total interest is every payment combined, minus the amount you borrowed. That is the number to put next to the monthly payment before you say yes.
Term is a price, not a comfort setting
A longer term lowers the payment by keeping you in debt after the car has lost much of its value. Cars depreciate quickly. A long loan pays down slowly. The gap between those two is how people end up upside down, owing more than the car would sell for.
A larger down payment lowers both the payment and that risk. So does a shorter term, if the payment still fits. Insurance, fuel, and maintenance are not in this loan. Add them before you decide the payment is affordable.
Get the price before you talk about the payment
Dealers can hit almost any monthly number by changing the term, the rate, or the add-ons. Ask for the out-the-door price first. Then bring a rate from a credit union or bank so the financing is a separate decision from the car.
Warranties, gap coverage, and protection packages belong in the fees field if you are actually buying them. Leaving them out of the calculator and then signing them at the desk is how a payment you checked becomes a payment you did not.
How to use the auto loan calculator
The payment is the amount financed, spread over the term at the APR. The amount financed is the price, plus sales tax on the price after the trade-in, plus fees, minus cash down and the trade-in. Total interest is every payment combined, minus the amount you borrowed.
- Enter the vehicle price before tax.
- Subtract the down payment and the trade-in. Add sales tax and fees so the amount financed is the real loan.
- Set the APR and the number of months.
- Compare the monthly payment with the total interest. A low payment can hide a long, expensive loan.
How the math works
What actually gets financed
Dealers often quote a payment before tax, fees, and the trade-in are settled. This calculator rolls those in first. Sales tax is charged on the price minus the trade-in, which is how many states tax a vehicle purchase.
Term versus total cost
A longer term lowers the payment and raises the interest, and it keeps you upside down longer because the car depreciates faster than a long loan pays down.
APR is the cost of borrowing
The APR includes interest. It is not the same as a promotional “payment.” A rate that looks ordinary on a large balance still produces thousands of dollars of interest over five or six years.
A $42,000 car financed for five years
The defaults use a $42,000 price, $4,000 down, a $6,500 trade-in, 6.5% sales tax, $650 of fees, and a 7.2% APR for 60 months.
Sales tax is about $2,308. The amount financed is about $34,458. The payment is about $686 a month, and the interest over the loan is about $6,676.
Terms worth knowing
- APR
- Annual percentage rate. The yearly cost of borrowing, used here as the loan interest rate.
- Amount financed
- Price plus tax and fees, minus the down payment and trade-in.
- Trade-in
- The value the dealer credits for your current car. It reduces both the price that is taxed and the loan.
- Upside down
- Owing more than the car is worth. Long terms make this more likely in the early years.
What to do with the number
Get the out-the-door price before you negotiate the monthly payment.
A larger down payment lowers the payment and the chance of owing more than the car is worth.
Check the rate from a credit union or bank before you sit down at the dealer.
Add insurance to your budget. It is not part of this loan payment.
Questions people ask
What this leaves out
The APR is fixed and interest compounds monthly.
Sales tax applies to the price minus the trade-in.
There is no balloon payment at the end.
Insurance, fuel, and maintenance are not in the payment.
These figures are estimates to help you understand the tradeoff. They are not tax, legal, insurance, or investment advice. A fiduciary can look at the same numbers in the context of the rest of your plan.