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 a sequence like 225/65R17. 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 the recommended pressure. If you have your owner's manual, the tire size appears in the specifications section, usually near the front or back.
The tire sidewall is the fastest option if you are at the vehicle. The door jamb sticker is the most reliable if you want to be certain you are reading the manufacturer's original recommendation, not a replacement tire someone else installed. The owner's manual is useful if you need the information later and want to write it down or photograph it.
Key Takeaways
- Tire size is printed on the sidewall of each tire in a code like 225/65R17, visible without tools.
- The driver's door jamb sticker shows the manufacturer's recommended tire size and pressure for your specific vehicle.
- Your owner's manual lists the tire size in the specifications or maintenance section.
- The three numbers and letters in a tire size code tell you the width, aspect ratio, and wheel diameter, which determine whether a tire will fit your vehicle.
Reading the tire sidewall code
The tire sidewall displays the size in a standardized format: a three-part code separated by a slash and a letter. For example, 225/65R17 breaks down as follows: 225 is the tire width in millimeters, 65 is the aspect ratio (the sidewall height as a percentage of the width), R means radial construction (standard for all modern tires), and 17 is the wheel diameter in inches.
You do not need to understand what each number means to use it. Write down or photograph the entire code exactly as it appears. When you shop for replacement tires, you can give this code to a tire shop or search for it online, and you will see only tires that fit your vehicle. The sidewall also shows the tire brand, model name, and load rating, but the size code is what matters for fitment.
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 body of the car. You will see a white or yellow sticker with black text. This sticker is the manufacturer's placard, and it lists the recommended tire size, the recommended tire pressure for the front and rear tires, and sometimes the maximum vehicle load.
The tire size on this sticker is what the vehicle manufacturer recommends for your specific model and year. This is the safest size to use if you are replacing tires, because it has been tested for your car's weight, handling, and braking. If the current tires on your car are a different size, that means a previous owner or a shop made a substitution — which may be legal but is not the original specification.
Using your owner's manual
If you have the printed manual that came with your car, the tire size appears in the specifications or maintenance section, usually within the first 20 to 30 pages. If you do not have the physical manual, you can find it online by searching for your vehicle's year, make, and model plus the word "manual" or "owner's manual PDF." Many manufacturers also host manuals on their websites.
The manual is useful if you want a permanent record or if you are shopping for tires away from your car. Write down the size exactly as it appears. Some manuals also list alternative tire sizes that are acceptable for your vehicle, though the first size listed is always the manufacturer's primary recommendation.
What to do if you cannot find the size
If the door jamb sticker is missing or illegible, and you do not have the manual, the tire sidewall is your fallback. Any tire currently on your car will show you a size that fits, even if it is not the original manufacturer recommendation. Write down that size and use it to search for replacements.
If all the tires are worn smooth or damaged and you cannot read the sidewall clearly, take a photo with your phone's flashlight and zoom in on the image. The code is usually raised or recessed enough to show up in a close photo. If you are still stuck, a tire shop can look at your vehicle and tell you the correct size in seconds — this is a free service they provide because they want your business.
Why tire size matters when replacing tires
Using the correct tire size ensures your speedometer reads accurately, your vehicle handles as designed, and your brakes perform as tested. A tire that is too small or too large can affect fuel economy, ride quality, and safety. Your vehicle's computer and suspension are calibrated for a specific wheel diameter, so staying within the manufacturer's recommendation is important.
Some tire shops will sell you a different size if you ask, and it may be legal in your state, but it voids the manufacturer's warranty on handling and braking performance. Sticking with the size on the door jamb sticker protects you if something goes wrong and you need to make a warranty claim.
Frequently Asked Questions
Can I use a different tire size than what the door sticker says?
Some alternatives are legal, but the door sticker size is the safest choice. If you want a different size, a tire shop can tell you which sizes are within acceptable limits for your vehicle. Deviating from the manufacturer's recommendation may affect your speedometer accuracy and void performance warranties.
What if the tire sidewall is too worn to read?
Take a close-up photo with your phone's flashlight and zoom in on the image. If that does not work, check the door jamb sticker or owner's manual. A tire shop can also identify your size by looking at the vehicle itself.
Does the tire size change if I buy a different brand?
No. The size code is a standardized measurement, not a brand-specific number. A 225/65R17 tire is the same size whether it is made by Michelin, Goodyear, or any other manufacturer. The brand and model name change, but the size code stays the same.
Is the size on the tire sidewall always the same as the door sticker?
Not always. If the current tires are replacements installed by a previous owner or a shop, they may be a different size. The door sticker shows the manufacturer's original recommendation; the sidewall shows what is actually on the car now. If they differ, the door sticker size is the correct one to use.
What do the numbers in the tire size actually mean?
The first number is width in millimeters, the second is sidewall height as a percentage of width, the letter R means radial construction, and the last number is wheel diameter in inches. You do not need to memorize this — just write down the entire code and give it to a tire shop when you are ready to buy.