Auto loans are the second-largest debt most Americans carry, and the decisions you make at the dealership — term length, down payment, rate source — determine whether you pay a few thousand or tens of thousands in total interest. Running the numbers before you sign is the single most valuable thing you can do before any vehicle purchase.
Shorter Terms Save Thousands
For a $35,000 principal at 6%, the 60-month contract payment is $676.65 with $5,598.89 interest. At 72 months it is $580.05 with $6,763.70 interest: $1,164.81 more. These examples exclude tax and fees. Compare payment size and the full ledger rather than assuming the lower payment costs less.
The Down Payment Sweet Spot
A larger down payment reduces borrowing under the same purchase terms. Vehicle value, loan rates and fees vary by car and offer, so a fixed down payment percentage does not ensure positive equity. Ask for the written out-the-door price, separate costs paid upfront from financed costs, and compare the resulting loan balance with the estimated vehicle value over the same ownership horizon.
Dealer vs. Bank Financing
Compare complete offers with the same purchase price, cash down, trade equity and ownership horizon. A $3,000 rebate on a $35,000 purchase leaves $32,000 financed; at 6% for 60 months, payments total $37,118.97. Financing $35,000 at 0% totals $35,000, so the 0% offer costs $2,118.97 less in this no-tax, no-fee example. If the rebate changes the tax base, adjust that assumption separately.