Car loan interest rates are the percentage of your auto loan principal a lender will charge you to borrow money. Interest rates are different from an annual percentage rate (APR), which is your interest rate plus extra loan fees. When shopping for vehicles, make sure to compare interest rates to interest rates, and not to APRs, to ensure you're getting the best deal possible, especially since your APR will typically be higher than your interest rate. Auto loan rates will vary based on your personal and economic circumstances. They are generally calculated based on your credit score and credit history, down payment, lender type, loan term, current national interest rates, and whether your car is new or used.