How to Check Tire Pressure
Check and adjust your tire pressure with a gauge and the number on your door jamb, and learn why the dashboard warning light comes on late.
We drove around for an embarrassingly long time before we learned how to do this. It felt like one of those adult skills that everyone else somehow picked up. Like parallel parking, or knowing when avocados are ripe.
It takes about 90 seconds, and it does save fuel, though less than the headline figure suggests. The US Department of Energy puts the gain at 0.6% on average, and up to 3% in some cases. That is worth having, but it will not transform your fuel bill. The more useful number on that same page runs the other way. Every 1 PSI you are down, averaged across all four tires, costs you about 0.2% in fuel economy, and tires lose pressure quietly enough that being several PSI down is the normal state of a car nobody checks.
Beyond fuel economy, correct tire pressure means better handling in corners, shorter braking distances, and tires that wear evenly across their surface. Underinflated tires wear faster on the edges. Overinflated tires wear faster in the center. Either way, you end up replacing them sooner than you should.
You will end up with all four tires, and the spare, at the pressure your car's maker set, checked while the tires are cold.
A tire pressure gauge is the only tool required. Digital gauges are easier to read, especially in bad light or if you are squinting at it in a parking lot. Pencil-style gauges (the ones with the sliding white stick) are cheaper, take no batteries, and work perfectly well. Either type fits in your glove box. You will also need access to an air pump if your tires turn out to be low. Most gas stations have one near the fuel pumps, sometimes free and sometimes coin-operated.
Get a tire pressure gauge
Check your glove box first. You might already have one tucked in there with the owner's manual. If not, gas stations and auto parts stores sell them. Digital gauges show a number on a small screen when pressed against the valve. Pencil gauges push out a calibrated white stick. Both are accurate enough for this job. Do not rely on the gauge built into a gas station air hose. It takes a beating, and you have no way of knowing whether it still reads true, so check with your own.
Find your car's recommended PSI
Open the driver's side door and look at the door jamb. There is a small sticker (usually white or yellow) that lists the recommended tire pressure for your specific vehicle. It will say something like "32 PSI front / 35 PSI rear" or give a single number for all four tires. This is the number you are aiming for. Some cars list different pressures for front and rear tires because of weight distribution. Write this number down or take a photo with your phone so you do not have to keep checking.
Heads up: The number molded into the tire sidewall is the maximum pressure the tire can handle, not the recommended pressure for your car. These are different numbers. The door sticker is what you want. We made this mistake for years and overinflated our tires.
Remove the valve cap
Each tire has a small black or silver cap on the valve stem, which is a short rubber or metal tube sticking out from the wheel. Twist the cap counterclockwise to remove it. Put it somewhere safe. A pocket works. We have lost at least four of these to parking lot gutters over the years. If you lose one, it is not critical for driving, but the cap keeps dirt and moisture out of the valve mechanism, and a valve that leaks slowly is the thing this whole guide is trying to catch. Replacements are sold in packs for pocket change at any auto parts counter.
Press the gauge onto the valve stem
Push the gauge firmly and straight onto the valve stem. It needs to sit in line with the stem, square against the end of it rather than leaning off to one side. You will hear a brief hiss of air escaping. That is normal and only loses a tiny amount of pressure. Hold the gauge steady for about one second until you get a stable reading. Digital gauges display a number automatically. Pencil gauges push out the white measurement stick, which stays extended until you manually push it back in. If the gauge hisses continuously or the reading seems wildly off, you are not making a good seal. Adjust your angle and press harder.
Compare to the recommended PSI
Look at the number on your gauge and compare it to the recommended PSI from the door sticker. If it matches (within 1 to 2 PSI), that tire is good. Move on to the next one. Check all four tires, because they can lose pressure at different rates depending on temperature, road conditions, and whether you have a slow leak somewhere. Note which tires are low and by how much.
Add or release air as needed
If a tire is below the target, drive to a gas station air pump. Attach the air hose to the valve stem and add air in short bursts of 3 to 5 seconds. Check the pressure with your gauge after each burst. It is easy to overshoot, so go slowly. If you added too much and the tire is over the target, press the small metal pin inside the center of the valve stem with your fingernail, a pen tip, or the back of the gauge. You will hear air hiss out. Release it in short bursts and recheck until you hit the target number.
Good to know: Check your tires when they are cold, and cold has a stricter definition than it sounds. The US Tire Manufacturers Association defines it as parked for at least 3 hours. Driving heats the air inside and inflates the reading by 2 to 4 PSI, so a warm tire that reads correct is actually low. If you have no choice but to drive to the pump, inflate to the door sticker figure plus that same 2 to 4 PSI, then recheck properly cold the next morning and correct from there.
Make it a habit by tying it to something you already do. At the first fill-up of each month, check all four tires and the spare before you pump. If one tire keeps coming up low between checks, it has a slow leak, so have a tire shop find it before it goes flat. If the dashboard warning light stays on when all four tires read correctly cold, have the monitoring system checked. And if a tire does go flat on the road, our guide on how to change a tire walks you through it.
Questions we get asked about this
Answers from experience, not a textbook.
Once a month, and that is the tire industry's own guidance rather than a rule of thumb. The US Tire Manufacturers Association says to check your tires at least once a month, and to include the spare. Tires naturally lose about 1 PSI per month through the rubber, even without a leak. We also check before road trips or any long highway drive, since extended high-speed driving on underinflated tires generates excess heat and increases blowout risk.
Yes. The US Tire Manufacturers Association says pressure drops 1 to 2 PSI for every 10 degrees Fahrenheit the temperature falls. If the temperature drops 30 degrees overnight during a cold snap, your tires could be 3 to 6 PSI lower by morning. This is why tire pressure warning lights often come on during the first cold spell of autumn. It does not mean you have a leak. Just top them off and recheck in a day. Know how late that light is allowed to arrive. The federal standard for tire pressure monitoring, FMVSS No. 138, does not require the warning until a tire is 25% below the recommended cold pressure. On a car placarded at 35 PSI, that is around 26 PSI, which is already deep into the range where handling, braking, and tire wear all suffer. The light is a backstop for a tire going flat, not a substitute for checking once a month.
Several things, all bad. Fuel economy drops because the tire creates more rolling resistance. The tire wears unevenly, with the edges wearing faster than the center, which shortens its lifespan significantly. Handling gets sluggish, especially in turns. Braking distance increases. In extreme cases, the tire can overheat from flexing too much and blow out at highway speeds. On fuel alone, the Department of Energy's figure of about 0.2% per PSI means all four tires sitting 5 PSI low costs you around 1% in mileage, before the effects on wear and handling.
Yes, especially before trips. A flat spare leaves you just as stranded as having no spare, and you only find out at the side of the road. Compact spares (donut tires) are commonly set to 60 PSI, but check the figure printed on the spare's sidewall or on the door placard. Full-size spares match your other tires. The tire industry's guidance is to check it monthly along with the others. Spares lose pressure just like regular tires.
Moderately overinflated tires (a few PSI over) are less dangerous than underinflated ones, but they still cause problems. The center of the tread wears faster. The ride becomes harsher because the tire absorbs less impact. Traction decreases because less rubber contacts the road. Stick within 1 to 2 PSI of the recommended number for the best balance of comfort, wear, and safety.
Car Owner Essentials
How to Check Tire Pressure
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