Where to find your tire size right now

Your tire size is printed in three places, and the easiest one depends on where you are. If you are standing next to your car, look at the sidewall of any tire — the size is stamped there in white letters. If you are inside the car or at home, open your driver's door and look at the sticker on the inside edge of the door frame; the tire size is listed there along with other vehicle specs. If you want to check without going outside, your owner's manual lists the correct tire size in the specifications section, usually near the front or back.

All three locations show the same information, so you only need to check one. The tire sidewall is fastest if you are at the car. The door jamb sticker is best if you want a permanent reference you can photograph. The owner's manual is best if you are shopping online and want to verify the size before you buy.

Key Takeaways

  • Tire size is printed on the sidewall of every tire in a format like 225/65R17, which tells you width, aspect ratio, construction type, and wheel diameter.
  • The door jamb sticker on the inside of your driver's door shows the manufacturer's recommended tire size for your vehicle.
  • Your owner's manual contains the tire size in the specifications section and is the best source if you cannot access the car.
  • The three locations may show different sizes if your car has been fitted with non-standard tires, so check the door jamb sticker to confirm what should be on your car.

Reading the tire sidewall

The sidewall of your tire displays the size in a standardized format that looks like this: 225/65R17. Each part of this code tells you something specific. The first number (225) is the tire width in millimeters. The second number (65) is the aspect ratio, which describes how tall the sidewall is as a percentage of the width. The letter (R) indicates radial construction, which is standard on all modern passenger vehicle tires. The final number (17) is the wheel diameter in inches.

You may also see additional markings on the sidewall: a load index (a two-digit number) and a speed rating (a single letter). These indicate how much weight the tire can carry and how fast it is rated to go. For most everyday driving, you do not need to match these exactly, but they should be at least equal to the original specifications listed on your door jamb sticker.

Checking the door jamb sticker

Open your driver's door fully and look at the inside edge of the door frame where it meets the car body. You will see a white or silver sticker with black text. This sticker lists the manufacturer's recommended tire size, along with the correct tire pressure for your vehicle. The tire size on this sticker is what your car was designed to use, and it is the safest reference point if you are replacing tires.

The door jamb sticker also shows different tire pressures for front and rear tires on some vehicles, and it may list a separate pressure for when the car is fully loaded. Write down or photograph this sticker before you go tire shopping, because tire shops will ask for this information and it ensures you get the right size and pressure for your specific vehicle.

Using your owner's manual

Your owner's manual contains the tire size in the specifications or technical data section, usually found in the first or last 20 pages. The manual lists the original equipment tire size — the size your car came with from the factory. This is the most reliable source if you do not have access to your car or if the door jamb sticker is damaged or missing.

If you no longer have the physical manual, you can search online for your vehicle's year, make, and model followed by "owner's manual PDF" to find a digital copy. Many manufacturer websites also allow you to search by vehicle identification number (VIN) to retrieve your specific manual. Once you have the manual, the tire size section is usually labeled "Tire Specifications" or "Recommended Tire Size."

What to do if the three sources show different sizes

If the tire sidewall, door jamb sticker, and owner's manual all show different sizes, trust the door jamb sticker first. That sticker reflects what the manufacturer engineered your car to use, and it is the safest choice. The sidewall may show a different size if someone previously installed non-standard tires, and the owner's manual may be outdated if your vehicle has been modified.

If you are unsure whether a tire size is safe for your car, contact a tire shop with your vehicle's year, make, model, and VIN. They can confirm whether the size you are considering is approved for your car and whether it will fit without rubbing or affecting your speedometer accuracy. Some tire sizes that are close to the original may be acceptable, but this varies by vehicle and should be verified before purchase.

Common tire size formats and what they mean

Most passenger vehicles use the P-metric system, which starts with the letter P (for passenger). A size like P225/65R17 follows the same width-ratio-construction-diameter pattern described earlier. Some vehicles, particularly trucks and SUVs, use the LT (light truck) system, which looks similar but may have different load ratings. European vehicles sometimes use the metric system without the P prefix, showing only 225/65R17.

All three formats convey the same basic information: width, aspect ratio, construction type, and wheel diameter. The differences are mainly in how they calculate load capacity. When you are shopping for replacement tires, match the format and all the numbers on your door jamb sticker as closely as possible. If you want to use a different size, a tire professional can tell you whether it is safe for your vehicle.

Frequently Asked Questions

Can I use a different tire size than what is on my door jamb sticker?

Some tire sizes close to the original may be acceptable, but this depends on your vehicle and should be verified by a tire shop before you buy. Using a significantly different size can affect your speedometer accuracy, fuel economy, and how your car handles. Always check with a professional if you are considering a non-standard size.

What if my door jamb sticker is missing or damaged?

Use your owner's manual or search online for your vehicle's specifications using the year, make, and model. You can also contact your vehicle's manufacturer with your VIN, or visit a tire shop with your VIN and they can look up the correct size in their system.

Does tire size affect my speedometer?

Yes. A tire that is significantly larger or smaller than the original will cause your speedometer to read inaccurately. This is why staying close to the manufacturer's recommended size matters. A tire shop can tell you whether a specific alternative size will affect your speedometer reading.

What is the difference between the tire size on the sidewall and the size on my door jamb sticker?

The door jamb sticker shows the manufacturer's recommended size for your car. The sidewall shows the actual size of the tire currently on your vehicle. If these differ, someone has installed non-standard tires. For replacement, use the door jamb sticker as your reference.

Where is the load index and speed rating on my tire?

Both appear on the sidewall after the wheel diameter. The load index is a two-digit number, and the speed rating is a single letter. For example, in 225/65R17 98H, the 98 is the load index and H is the speed rating. These indicate weight capacity and maximum speed, and they should match or exceed your original tire specifications.