How to check tire pressure (and how often you should)

Checking tire pressure takes about five minutes and a gauge that costs a few dollars. You don't need to be a car person. Here's how to do it, how often, and how to get it checked for free if you don't own a gauge.

The short version: check your tires cold, once a month, against the number on your driver's door label, not the number on the tire.

What you need

A tire pressure gauge. Any of the three common kinds works: a pencil gauge (a stick that slides out), a dial gauge, or a digital one. Digital and dial gauges are easier to read.
Your car's recommended pressure. It's on a label on the driver's door frame (on some cars, the glove box or fuel door) and in the owner's manual. Front and rear can be different.

No gauge? Skip to checking without one.

How to check tire pressure, step by step

Check when the tires are cold. NHTSA counts tires as cold when the car hasn't been driven for at least three hours. First thing in the morning is easiest. After driving, tires read a few PSI higher than they really are.
Find your number. Read the recommended pressure (in PSI) on the label on the driver's door frame. Don't use the number molded into the tire's sidewall. That's the most the tire can hold, not what your car needs.
Take the cap off the valve stem. It's the small rubber or metal stem near the edge of the wheel. Put the cap in your pocket so it doesn't roll away.
Press the gauge straight onto the valve, firmly and quickly. A short hiss is normal. If it keeps hissing, the gauge isn't seated; press again more squarely.
Read it. Compare the reading with your door label. If it seems off, take a second reading; the first one is sometimes wrong if the gauge went on at an angle.
Repeat on all four tires, even ones that look fine. A tire can be well below its recommended pressure and still look normal. Check the spare too; NHTSA says to include it in the monthly check, and it's often the one that's flat when you need it.
Add air if any tire is low, then check it again. Our guide to putting air in your tires at a gas station walks through the air machine.
Put the valve caps back on. They keep dirt and moisture out of the valve.

If a tire reads too high

Press the small pin in the center of the valve with the back of the gauge (or a fingernail) to let air out in short bursts, then check again. If you just drove, wait before letting any out: a warm tire reading a few PSI over the label is normal and will settle as it cools.

How often should you check tire pressure?

At least once a month, spare included, which is what NHTSA recommends. Also check:

Before a long road trip, especially with a full car or a trailer.
When the weather turns cold. Pressure drops about 1 PSI for every 10°F the temperature falls, so the first cold mornings of fall often leave tires low overnight.
When the tire pressure light comes on. The light only turns on once a tire is about 25% low, so it's a late warning. Here's what to do when the light comes on.

Monthly checks matter because tires lose air slowly on their own, and a tire that's 15% low won't trigger the light but still wears faster, handles worse and costs you gas.

How to check tire pressure without a gauge

Your dashboard. Some cars, usually ones with a sensor in each wheel, show each tire's pressure on the dash or in the vehicle menu. Many others only have the warning light, which doesn't show a number. Your owner's manual says which kind you have.
The air machine's gauge. Many gas station air machines have a gauge built into the hose, and newer ones let you set the PSI and stop automatically when the tire is full.
A tire shop, for free. Discount Tire, Les Schwab and Sullivan Tire check and fill tires at no charge during store hours, and Belle Tire has free self-service air at every location, around the clock.

Don't trust the squeeze test or eyeballing the bulge. A tire that's several PSI low usually looks exactly like one that's full.

Where to check and fill your tires for free

You can check pressure anywhere, but if a tire is low you'll need air. Gas stations known for free air at most stores include Wawa, Sheetz, QuikTrip and Kwik Trip. By law, every gas station in California has to give free air to customers who buy fuel, and every station in Connecticut has to provide it while it's open. Search our map of free air for tires near me to find the closest spot, with hours and driving time.

What the numbers mean

Most cars and minivans call for 30 to 35 PSI, SUVs and crossovers 32 to 35, and pickups 32 to 40 on regular tires, but always go by your door label. Our tire pressure guide has typical numbers for cars, SUVs, trucks and spare tires.

Low on air right now? See the closest free air, open now, with driving times. Find free air near me

Questions

How often should you check tire pressure?

At least once a month, plus before a long trip and when the weather turns cold. That's NHTSA's advice, and it includes the spare. Tires slowly lose air on their own, so a monthly check catches it before it matters.

Should I check tire pressure hot or cold?

Cold. NHTSA counts tires as cold when the car hasn't been driven for at least three hours, so first thing in the morning is ideal. Driving warms the tires and raises the reading by a few PSI, which hides how low they really are.

What should my tire pressure be?

Use the number on the label on the driver's door frame (or in the owner's manual). Don't use the number on the tire's sidewall; that's the maximum the tire can safely hold, not what your car needs. Most cars call for 30 to 35 PSI.

Can I check tire pressure without a gauge?

Yes. Some cars show each tire's pressure on the dashboard. Many gas station air machines have a built-in gauge, and tire shops like Discount Tire and Les Schwab will check your tires for free during store hours. Squeezing or looking at a tire isn't reliable.

Is it bad to check tire pressure too often?

No. Each check lets out a tiny puff of air when you press the gauge on, but that's far too little to matter. Just make sure you screw the valve caps back on.