Auto loan interest rates are determined through risk-based pricing. If a lender determines you're more at risk of defaulting on your loan because of your credit score and other factors, you'll typically be charged a higher interest rate to compensate for that risk.
Factors that can impact your auto loan interest rate include the following:
Credit score and history
Even if your credit score is relatively high, you may still end up with a higher interest rate if there are negative items on your credit report, such as missed payments, collection accounts, repossessions, and bankruptcy.
Loan term
The longer your repayment term, the more risk it carries for the lender—both that you might default on your payments and that market interest rates may increase, making your loan less profitable than new loans.
You may be able to score a lower interest rate by going with a shorter repayment term. Just remember that shortening your loan term will also increase your monthly payments.
Down payment
Putting more money down on your vehicle purchase reduces how much you need to borrow, thereby decreasing the risk associated with your loan. As a result, a larger down payment may result in a lower interest rate.
New vs. used vehicle
Auto manufacturers provide many incentives for car buyers to purchase new vehicles, including lower interest rates through their financing companies. Other lenders, including banks and credit unions, may also lower their rates to compete. In contrast, if you're buying a used car, there's no incentive for lenders to offer lower rates, which results in higher rates on average.
Income and Debt
Lenders will consider your debt-to-income ratio (DTI), or how much of your gross monthly income goes toward debt payments. A high DTI may be a sign that you can't take on any more debt without putting stress on your budget and may result in a higher interest rate.
The lender
Each lender has its own criteria for determining auto loan interest rates and may have differing starting and maximum rates.
Whatever auto loan interest rate you qualify for, it'll be represented in the form of an annual percentage rate (APR). Your APR will affect your monthly payment amount as well as how much the loan will cost you over the life of the loan. Due to a process called amortization, you'll pay more interest at the beginning of the loan term than at the end.