How the financed amount is built
The price on the window sticker is rarely the amount you finance. Sales tax and dealer fees are added on top, then your cash down payment and any trade-in value are subtracted. The result is the principal the lender actually charges interest on.
That principal is then repaid as a standard amortized loan: equal monthly payments where the interest portion is largest at the start and shrinks as the balance falls, so more of each later payment goes to principal.
Making sense of the numbers
The monthly payment is your fixed obligation for the life of the loan. The loan amount confirms how much you borrowed after down payment and trade-in, total interest is the financing cost, and total cost is principal and interest combined.
The donut chart splits your total payments into the amount borrowed versus interest, while the balance line shows the loan winding down year by year — useful for judging when you would owe less than the car is worth.
Ways to lower the cost
A smaller principal and a shorter term are the two biggest levers on a car loan.
- Put more down or use a trade-in to shrink the amount financed.
- Favor a shorter term; long 72- or 84-month loans cut the payment but balloon the interest.
- Secure financing from a bank or credit union before visiting the dealer to compare offers.
- Watch for negative equity if you roll an old loan balance into the new one.
What this does not include
This is the loan cost only. Ongoing ownership costs — insurance, fuel, registration, maintenance and depreciation — are separate and often exceed the financing itself over the years you keep the vehicle.
Formula
principal = price + price·tax/100 + fees − down − tradeIn; r = annualRate/100/12; payment = P·r / (1 − (1+r)⁻ⁿ)Frequently asked questions
- Is sales tax applied to the price before or after the trade-in?
- This calculator applies sales tax to the full vehicle price. Some states tax the price after the trade-in credit, which would lower the financed amount.