Your tire size is the sidewall and door-sticker code, such as P215/55R17 94V, that matches width, height, wheel size, load, and speed.
If you need the right fit, the answer is usually right in front of you. Start with the sticker on the driver’s door jamb. It lists the size your vehicle was built to use, along with the cold tire pressure. That sticker beats guesswork.
You can also find a similar code on the tire sidewall and in the owner’s manual. Read it piece by piece, and buying replacements gets a lot easier.
What Is My Tire Size On The Door Sticker?
The driver-side placard is the fastest place to check. On many cars, it sits on the door jamb or door edge. On some vehicles, the label may be on the glove-box door or inside the trunk lid. It shows the tire size and pressure approved for that model and trim.
That’s why the placard should come before the sidewall when you’re buying new tires. The sidewall tells you what is mounted on the car today. The placard tells you what the car was meant to run. If a past owner changed wheels or fitted a winter set, the placard keeps you from copying a bad match.
Why The Placard Comes First
The label may show front and rear pressures, spare-tire details, and, on some cars, more than one approved size. Some vehicles use different front and rear tires. Buying four identical tires for a staggered setup can turn into a costly mess.
Use the owner’s manual if the sticker is worn or missing. Compare it with the current sidewall. If they don’t match, go with the vehicle spec, not the tire now on the wheel.
Other Places People Miss
- The owner’s manual, often in the glove box
- The spare-tire label, if your vehicle uses a compact spare
- An old invoice from the same wheel setup
- A photo of the placard from your last tire change
This quick check stops a common mistake: reading only the wheel size. A 17-inch wheel can wear many tire sizes, and only one may be right for your car.
Finding Your Tire Size From The Sidewall Code
If you can’t get to the placard right away, read the sidewall. You’ll see a molded code made of letters and numbers. Michelin’s finding your tire size page names the same three common places to check: the sidewall, the manual, and the vehicle placard.
Say your tire reads P225/65R17 102H. Read it left to right and the code stops looking cryptic.
| Sidewall Part | What It Means | What To Watch |
|---|---|---|
| P | Passenger-car tire type | LT means light truck; T often marks a temporary spare |
| 225 | Tire width in millimeters | A wider tire may rub if the wheel or offset changed |
| 65 | Aspect ratio, or sidewall height as a share of width | A lower number means a shorter sidewall |
| R | Radial construction | Most modern road tires use radial construction |
| 17 | Wheel diameter in inches | This must match your wheel exactly |
| 102 | Load index | Replacement tires should meet or beat the required load rating |
| H | Speed rating | Do not drop below the spec your vehicle calls for |
| XL or SL | Extra-load or standard-load class | Match the class when your vehicle was fitted for it |
How To Read A Real Example
Take 225/65R17. The tire is 225 millimeters wide. Its sidewall height is 65 percent of that width. It fits a 17-inch wheel. The service description at the end tells you how much weight the tire can carry and the speed category it is built for. Those last two parts matter as much as the size itself.
Many drivers skip that piece. Two tires can share the same width, ratio, and wheel diameter while carrying different load indexes or speed ratings. If your old tire says 94V and the bargain one says 91H, the spec is not the same.
When The Tire On The Car Gives The Wrong Answer
Copying the sidewall can be the wrong move. A used car may come with a size picked by the last owner. A summer setup may differ from the winter set in your garage. Some cars run wider rear tires than front tires. Aftermarket wheels can change the code again.
That doesn’t always mean the current setup is bad. It does mean you should verify before you buy. If you changed wheels on purpose, write down the full size, wheel width, load index, and speed rating for that setup. If you didn’t change anything yourself, trust the placard and manual first.
NHTSA’s tire safety ratings and labeling points buyers to tire labels and sidewall markings when comparing options. That matters when two tires look alike online yet differ in grade, load, or intended use.
Load, Speed, And Tire Type Still Count
A tire size is not just the big middle numbers. You still need the right tire type for the vehicle and season you drive in. Passenger tires, light-truck tires, compact spares, run-flats, and winter tires can use similar-looking codes but behave in different ways on the road.
If your car came with run-flat tires or a maker-specific tire marking, swapping to a different build can change ride feel, handling, or clearance. Read the full spec before you click “buy.”
| Situation | Best Place To Check | What Must Match |
|---|---|---|
| Stock daily driver | Door placard | Size, load index, speed rating, pressure |
| Sticker missing | Owner’s manual | Factory-approved size and pressure |
| Used car with unknown tire history | Placard plus manual | Original fitment, not just current sidewall |
| Front and rear are different | Read all four tires and placard | Axle-specific sizes |
| Aftermarket wheels | Your wheel-and-tire records | Diameter fit, clearance, load, speed |
| Compact spare | Spare sidewall and vehicle label | Temporary-use instructions |
How To Check Tire Size Without Guessing
If you want a clean answer in under two minutes, use this order:
- Open the driver’s door and photograph the placard.
- Write down the full tire size, not just the wheel diameter.
- Note the load index and speed rating at the end of the code.
- Check whether front and rear sizes differ.
- Read the current sidewall and see if it matches the placard.
- Open the owner’s manual if the label is missing or hard to read.
That routine cuts out most ordering errors. It also gives you the details a shop or online retailer will ask for. If your vehicle has more than one approved size, choose the one that matches your current wheel diameter unless you are changing wheels on purpose.
Mistakes That Trip People Up
The first mistake is buying by vehicle model alone. Trim level, engine package, and wheel option can change tire size. The second mistake is reading the max pressure on the sidewall and using that as your day-to-day target. The correct cold pressure is usually on the vehicle placard, not in the big molded letters on the tire.
The third mistake is stopping at the first numbers that look familiar. A tire marked 225/65R17 is not a match for 225/60R17, though the width and wheel size line up. That shorter sidewall changes overall diameter. Your speedometer, ride height, and clearance can all shift with it.
Last, don’t ignore the service description. A lower load index or speed rating can leave you with a tire that fits the wheel yet does not meet the vehicle’s needs. When you read the whole code, the right tire usually stands out fast.
A Straightforward Way To Buy The Right Tire
Start with the placard. Use the owner’s manual if the label is gone. Use the sidewall as a cross-check, not as your only source, unless you already know the current setup matches factory spec. Match width, aspect ratio, construction, wheel diameter, load index, and speed rating. Then match the front and rear axle if your car uses two sizes.
Once you know where the code lives and what each piece means, the question gets a lot less fuzzy. You’re reading a fitment label, and that gives you a clear, shop-ready answer.
References & Sources
- Michelin.“Choosing the Right Tire Size for Your Vehicle.”Shows where to find tire size information on the sidewall, in the owner’s manual, and on the vehicle placard.
- National Highway Traffic Safety Administration (NHTSA).“Tire Safety Ratings and Awareness.”Explains tire labeling, ratings, and buyer information tied to sidewall markings.