Auto Payment Calculator View Calculator There's more to figuring out actual auto loan payments than just calculating the payments on the vehicle's sticker price. Use this calculator to find out how much your auto loan payments will be. Enter the price of the vehicle, the sales tax percentage you will pay on the new vehicle, and other charges that will be financed, like tags and registration, or dealer prep and delivery charges. Then enter any cash, trade-in, and dealer rebates that you will use as a down payment and the interest rate and length of the loan you are considering. You can even enter an additional amount you intend to add to your payment each month to work down your principal and the calculator will show you the anticipated payoff time. Learn more about putting this calculator or other calculators on your website.