Your tire size is printed on the sidewall of every tire on your vehicle

The easiest place to find your tire size is on the side of the tire itself. Look at the black rubber wall of any tire on your car — you will see a series of letters and numbers stamped into it. This marking includes your tire size along with load rating, speed rating, and manufacturing date. You do not need any tools or special knowledge to read it; the information is right there in plain sight.

If you cannot see the tires clearly or prefer not to bend down to check them, your vehicle's door jamb label also lists the tire size. Open the driver's side door and look at the frame where the door closes — you will see a sticker with vehicle specifications. This label shows the recommended tire size for your vehicle, which is what you should use when replacing worn tires.

Key Takeaways

  • Your tire size appears on the sidewall of each tire as a combination of letters and numbers, such as P215/65R15.
  • The door jamb sticker on your driver's side door lists the manufacturer's recommended tire size for your vehicle.
  • The owner's manual contains your tire size and specifications in the tire or maintenance section.
  • Each number and letter in the tire size code means something specific about width, aspect ratio, construction, and wheel diameter.
  • Using the correct tire size matters for safety, fuel economy, and how your vehicle handles.

Reading the tire sidewall code

A typical tire size looks like this: P215/65R15 95H. Each part of this code tells you something different. The P at the start means passenger vehicle tire. The 215 is the tire width in millimeters. The 65 is the aspect ratio — the height of the tire sidewall as a percentage of the width. The R means radial construction, which is standard on all modern tires. The 15 is the wheel diameter in inches.

The numbers at the end, like 95H, describe load and speed ratings. The 95 is the load index, which tells you how much weight the tire can carry. The H is the speed rating, indicating the maximum speed the tire is designed for safely. You do not need to memorize what each number means — you only need to know that when you buy replacement tires, matching these numbers ensures your new tires work the same way as the originals.

Checking your vehicle's door jamb label

The door jamb sticker is often easier to read than bending down to look at a tire. When you open your driver's side door fully, look at the vertical frame where the door seals against the body of the car. You will see a white or silver sticker with black text. This label lists several specifications, including the recommended tire size, the correct tire pressure for your vehicle, and the vehicle's gross weight rating.

The tire size on the door jamb is what the manufacturer recommends for your specific vehicle model and year. This is the size you should use when replacing tires. Some vehicles may have multiple acceptable sizes listed, which means you have a small range of options, but the primary recommendation is usually listed first. If you cannot find the door jamb label, check the inside of the fuel door or the glove box — some manufacturers place it in these locations instead.

Finding tire size in your owner's manual

Your vehicle's owner's manual contains a section dedicated to tires and wheels, usually near the front or in the maintenance section. This section lists your tire size, recommended tire pressure, and instructions for tire rotation and replacement. If you have the physical manual, flip to the index and search for "tires" or "wheels." If you have lost your manual, you can search online for your vehicle's year, make, and model followed by "owner's manual PDF" to find a digital copy.

The manual also explains what each number in the tire size means and provides guidance on when to replace tires. Some manuals include a tire pressure monitoring system explanation and instructions for resetting the system after you change tires. Having this reference is useful not just for finding your tire size, but for understanding tire maintenance throughout your vehicle's life.

What to do if you cannot find your tire size

If none of these methods work — perhaps the sidewall is too worn to read clearly, the door jamb sticker is missing, and you do not have your manual — you can contact your vehicle's manufacturer directly. Call their customer service line with your vehicle identification number (VIN), which you can find on your dashboard at the base of the windshield on the driver's side. The manufacturer can tell you the correct tire size in seconds.

You can also visit a tire shop and ask them to look up your vehicle's specifications. Most shops have computer systems that can retrieve this information using your VIN. This is a free service — they do this regularly for customers who need to know their tire size before shopping. You are under no obligation to purchase tires from them just for looking up the information.

Why matching your tire size matters

Using the correct tire size is not just about fitting the tire onto the wheel. The size affects your vehicle's speedometer accuracy, fuel economy, handling, and how the suspension performs. A tire that is too small or too large can cause your speedometer to read incorrectly, which affects how you judge your actual speed. It can also change your vehicle's ground clearance and how it handles in turns.

Insurance and safety considerations also explore. If you are in an accident and your tires are not the manufacturer's recommended size, your insurance company may question whether the vehicle was maintained properly. Using the correct size protects you legally and ensures your vehicle performs as designed. When in doubt, match the size shown on your door jamb label — that is always the safest choice.

Frequently Asked Questions

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

Some vehicles have a range of acceptable sizes, which your door jamb label may list. However, you should never use a size outside the manufacturer's recommendations. Using an unapproved size can affect your speedometer, fuel economy, and how your vehicle handles. If you want to change sizes, check your manual or contact the manufacturer first.

What if the numbers on my tire sidewall are worn and hard to read?

Check your door jamb label or owner's manual instead — these are much easier to read. If both are unavailable, any tire shop can look up your tire size using your vehicle's VIN at no cost. You can also call your vehicle's manufacturer with your VIN and they will tell you the correct size.

Does tire size affect my gas mileage?

Yes. A larger tire can reduce fuel economy because it requires more energy to rotate. A smaller tire may improve fuel economy slightly but can affect speedometer accuracy and handling. Stick with the manufacturer's recommended size to maintain the fuel economy your vehicle was designed for.

What is the difference between the tire size on my door jamb and the size on my actual tires?

The door jamb shows the manufacturer's recommendation. Your actual tires may be a different size if they were replaced with the wrong size or if a previous owner changed them. When you replace your tires, use the size on the door jamb, not the size currently on your vehicle, unless you are certain the current size is correct.