If the car is a 2003 or newer, the correct tire pressure is found on the driver's side door on a placard along with the weight of the vehicle. For cars older than 2003, the information is also displayed on a placard, but it may be in another location.
In addition to listing tire pressure on the doorjamb, vehicles that were made in 2003 to the present must have the information listed in the owner's manual. Other mandatory items listed in the owners manual include tire labeling, tire care, vehicle load limits and a glossary of tire terms.
Vehicles that were made between 1968 and 2003 may have placards in areas other than the doorjamb of the driver's side. On Ford sedans, for instance, these placards are found on the rear passenger doorjamb. On other cars, the placard is located in the glove box or in the engine compartment. Many vehicle manufacturers also list the tire pressure in the owner's manual.
Sometimes, people incorrectly believe that tires should be inflated based on the pounds per square inch number listed on the sidewall of the tire. This number, however, identifies the maximum pressure that the tire is rated to hold. This is not the correct pressure for every vehicle, however. In fact, most vehicle manufacturer's recommend a tire pressure that is less than the maximum pressure.