Calculating your auto loan rates by credit score is easy if you know the formula used or if you know that there are a number of sites online that will perform the calculations for you. One of the best sites for calculating your auto loan interest rate based on your credit score is by using the site run by the company that determines those credit scores: FICO. AT the MyFICO website, you can calculate your national interests by your credit score, or you can drill down and specify what state you live in, your credit score and the term of your new car loan.
For more info, see New Car Auto Loan Rates: Average Price List