Direct answer
Put in the pressure listed on your vehicle's door-jamb placard, not the number molded into the tire sidewall. That placard figure is usually between 30 and 35 psi for passenger cars, but it varies by make, model, and load, so the sticker on your specific car is the only number that matters. Check the pressure when the tires are cold, and top up whenever a tire falls more than a few psi below that target [1].
Where Do I Find The Correct Tire Pressure For My Car?
The recommended pressure for your vehicle is printed on a label in the driver's side door jamb, and it is the figure the manufacturer engineered the car to run on [2]. That same sticker often lists separate front and rear pressures, because many vehicles carry more weight over one axle and need a higher number there [2]. You will also find the specification repeated in the owner's manual and sometimes on the inside of the fuel filler door, which makes it easy to confirm if the door sticker has worn away [2].
It helps to understand why the placard exists at all. Engineers set that pressure to balance grip, braking distance, ride comfort, and even fuel economy across the whole vehicle, so it is a system-level recommendation rather than a tire-level one [2]. If you cannot read the door sticker, the owner's manual for your exact model year is the next best authority, and a dealership parts desk can look it up from your VIN [2].
One practical habit is to photograph the placard with your phone the first time you find it. That way you always have the correct number on hand at the air pump, even in poor light or bad weather [2].
Should I Use The Number On The Tire Sidewall Or The Number On The Door Placard?
Use the door placard, because the number on the sidewall is a maximum, not a recommendation. The sidewall figure states the highest cold pressure the tire can safely hold under its maximum rated load, and inflating to that level on a normal passenger car causes the tread to crown in the center and wear unevenly [3]. It also reduces the contact patch, which hurts grip and braking, and it makes the ride noticeably harsher [3].
The sidewall marking is still useful, but for a different purpose. It tells you the tire's load and speed ratings and its maximum capacity, which matters when you are matching a replacement tire to your vehicle [3]. Treat it as a ceiling you should stay well under during everyday driving, not as a target to hit [3].
There is one legitimate exception worth knowing. If you are carrying a heavy load or towing, some manufacturers specify a slightly higher pressure in the rear tires, and that adjusted figure will still be printed on the placard or in the manual rather than on the tire [3]. When in doubt, follow the vehicle documentation, not the rubber [3].
How Do I Check And Adjust My Tire Pressure Correctly?
Check the pressure when the tires are cold, meaning before you have driven more than about a mile, because heat from driving raises the reading and can mask an underinflated tire [4]. Remove the valve cap, press a quality gauge firmly onto the valve stem, and read the number; do not trust a visual inspection, since a tire can look fine while sitting several psi low [4]. Compare what you read against the placard figure for that position, front or rear [4].
If a tire is low, add air in short bursts and re-check after each burst rather than holding the nozzle down and guessing [4]. Overinflation is easy to create this way and just as easy to avoid, and a few seconds of patience keeps you near the target instead of overshooting it [4]. Once every tire matches its specification, refit the valve caps, since they keep dirt and moisture out of the stem [4].
Make this a monthly routine and repeat it before any long trip, because tires lose roughly one psi per month even when they are in good condition [1]. A slow leak, a nail, or a damaged valve can turn a small drop into a real problem, and catching it early is far cheaper than replacing a ruined tire [1]. If one tire keeps dropping while the others hold steady, have it inspected for a puncture or a leaking seal [1].
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FAQ
What is the most common tire pressure for a passenger car?
Most passenger cars run between 30 and 35 psi, but the exact figure depends on the make, model, and load, so the door-jamb placard always overrides any general range [1].
Can I just inflate to the maximum pressure printed on the tire?
No. That number is the tire's maximum cold capacity, not a recommendation, and running at it causes uneven wear and reduced grip [3].
Should I check my tires when they are hot or cold?
Check them cold, before driving more than a mile, because heat raises the reading and can hide a genuinely low tire [4].
How often should I add air?
Check monthly and before long trips; tires typically lose about one psi per month even when healthy, and a persistent drop on one tire points to a leak [1].
What happens if I ignore a slightly low tire?
Underinflation is a leading cause of tire failure, and it also increases rolling resistance, which costs you fuel and shortens tire life [1].