What a DOT number is and where to find it

A DOT number is a unique identifier assigned by the U.S. Department of Transportation to tires manufactured in the United States. It appears on the sidewall of every tire and tells you the week and year the tire was made. The DOT number is a string of characters that typically looks like this: DOT XXXX XXXX XXXX, where the last four digits are the most important — they show the week and year of manufacture.

You can find the DOT number on the outer sidewall of your tire, usually near the bottom. Look for the letters "DOT" followed by a series of numbers and letters. The final four digits are what matter most: the first two digits represent the week of manufacture (01 through 53), and the last two digits represent the year. For example, a tire marked 3519 was made in the 35th week of 2019.

If you cannot see the DOT number on the outer sidewall, check the inner sidewall — the side facing the vehicle's body. Some tires have the complete DOT number on both sides, while others only show it on one side.

Key Takeaways

  • The DOT number on your tire's sidewall shows the week and year it was manufactured, with the last four digits being the critical ones.
  • The first two of those four digits represent the week (01–53), and the last two represent the year (for example, 19 means 2019).
  • You can check your tire's age by reading the DOT number directly from the sidewall without any tools or online lookup.
  • Tire manufacturers and the NHTSA use DOT numbers to track recalls, so knowing yours helps you determine if your tires are affected.

Why the manufacture date matters for your tires

Tire age affects safety and performance, even if the tread looks fine. Rubber degrades over time as it is exposed to heat, sunlight, and ozone, regardless of how much the tire has been driven. The Tire Industry Association recommends replacing tires that are 10 years old or older, and many tire shops will refuse to sell tires that are more than 6 years old as new stock.

If your vehicle has been sitting in storage or you bought used tires, the DOT number tells you exactly how old they are. A tire that looks new but was manufactured 8 years ago may have internal damage you cannot see. Checking the DOT number takes seconds and can prevent a blowout or loss of traction.

Reading the DOT number step by step

Start by locating the DOT marking on your tire's sidewall. You will see the letters "DOT" followed by a series of characters. The last four digits are what you need to focus on — ignore everything before them.

Take the last four digits and split them into two pairs. The first pair is the week number (ranging from 01 to 53). The second pair is the year number. If the year digits are 23, the tire was made in 2023. If they are 09, it could be 2009 or 2019 — tires made before 2000 use a different format, so if you see a single digit or two digits under 10, the tire is likely from the 1990s or very early 2000s.

Write down the complete DOT number if you plan to check for recalls or discuss the tire with a mechanic. You will need it if the tire is part of a manufacturer recall.

Checking for tire recalls using the DOT number

The National Highway Traffic Safety Administration (NHTSA) maintains a database of all tire recalls. You can search by DOT number, tire brand, or model at safercar.gov. Enter your complete DOT number in the search field, and the system will show whether your tire has been recalled and what the issue is.

If a recall is found, the NHTSA page will tell you the reason for the recall, the potential hazard, and what the manufacturer is doing to fix it. Some recalls require replacement; others may involve a repair or inspection. The page will also provide contact information for the tire manufacturer so you can report your tire or request a replacement.

Keep in mind that not all tires are recalled, and a tire with no recall does not mean it is safe indefinitely. Use the DOT number to confirm the age, and replace tires based on wear, damage, or age — whichever comes first.

What to do if you cannot read the DOT number

If the DOT number is worn, faded, or damaged, you have a few options. Try cleaning the sidewall with a damp cloth and looking again in good light — sometimes the number is just dirty. If the number is still illegible, a tire shop can read it for you or help you identify the tire by brand and model.

If you are buying used tires and the seller cannot provide the DOT number, ask them to show you the tire in person so you can read it yourself. Never buy a used tire without knowing its age and condition. If the DOT number has been deliberately removed or altered, that is a red flag — avoid that tire.

DOT number versus other tire markings

The sidewall of a tire contains several pieces of information, and it is straightforward to confuse them. The tire size (like 225/65R17) tells you the width, aspect ratio, and wheel diameter. The load index and speed rating (like 95H) tell you how much weight the tire can carry and how fast it can safely go. The DOT number tells you when it was made.

The DOT number is the only marking that reveals the manufacture date. Other numbers on the sidewall, such as batch codes or serial numbers used by the manufacturer, do not indicate age. If you see multiple numbers on the sidewall, look specifically for the one that begins with "DOT" — that is the one you need.

When to replace tires based on age alone

Even if your tires have plenty of tread, most safety experts recommend replacing them at 10 years old. Some manufacturers and tire shops are more conservative and suggest replacement at 6 years. Check your vehicle's owner manual and your tire manufacturer's recommendations for guidance specific to your tires.

If you drive in hot climates, park in direct sunlight, or store your vehicle for long periods, tires may degrade faster than the 10-year guideline. Use the DOT number to track age, and have a mechanic inspect tires that are 5 years or older for signs of cracking, hardening, or other damage that might indicate the rubber is breaking down.

Frequently Asked Questions

How do I know if my tires are too old to drive on?

Check the DOT number on the sidewall to find the manufacture date. If the tires are 10 years old or older, most experts recommend replacement regardless of tread depth. If they are between 5 and 10 years old, have a mechanic inspect them for cracks, hardening, or other signs of deterioration.

Can I use the DOT number to find out who made my tire?

The DOT number does not identify the manufacturer — it only shows when the tire was made. To find the manufacturer, look at the tire brand name printed on the sidewall. The DOT number itself is just a tracking code for safety purposes.

What if the last two digits of the DOT number are 99 or 00?

Tires made before 2000 use a different DOT format. A tire marked with 99 or 00 in the last two positions was likely made in the 1990s or 1999–2000. These tires are well over 20 years old and should be replaced when ready, regardless of tread appearance.

Do I need the DOT number to get a tire replaced under warranty?

You do not need the DOT number to replace a tire under warranty, but having it helps. If the tire is defective, the manufacturer may ask for the DOT number to verify the date of manufacture and confirm the warranty is still valid. Bring the tire or the number with you when you visit the tire shop.

Is there a tool or app that reads the DOT number for me?

No app can read the DOT number from a photo — you have to read it directly from the tire sidewall. However, once you have the number, you can enter it into the NHTSA recall database at safercar.gov to check for recalls and get detailed information about your specific tire.