Kentucky Sales Tax on Car Purchases: Vehicles purchases are some of the largest sales commonly made in Kentucky, which means that they can lead to a hefty sales tax bill. This page covers the most important aspects of Kentucky's sales tax with respects to vehicle purchases. For vehicles that are being rented or leased, see see taxation of leases and rentals. Kentucky collects a 6% state sales tax rate on the purchase of all vehicles. The maximum tax that can be owed is 375 dollars. In addition to taxes, car purchases in Kentucky may be subject to other fees like registration, title, and plate fees. You can find these fees further down on the page.