Check the sidewall of the tire for the size code
Look for a format like P215/65R15 or 225/45R17
Read the owner’s manual for the recommended tire size
Check the driver’s door jamb sticker for factory tire size
Look at the fuel door label if your vehicle has one
Measure the tire width, aspect ratio, and rim diameter if the size is worn off
Use the vehicle’s VIN or dealership records to confirm the original tire size
Compare all four tires to make sure they match the same size code