It's three numbers printed on the tire you already own. We'll point right at them, then load your size as you type. No tools, no crawling under the car, no problem.
Your tire size is printed in two easy-to-find spots:
Check the side of any tire on your car — the size is printed right into the rubber.
Open the driver's door and look at the sticker on the body frame.
Type the numbers from your tire — slashes optional. Matching sizes load as you go; tap the right one.