Tire DOT Code: How to Read the Date and Plant Info

What is the DOT code?

Every tire sold in the United States must bear a DOT code, a marking required under federal tire identification regulations. The DOT symbol confirms the tire meets federal safety standards and is used for recall and recordkeeping purposes. You'll find it molded into the sidewall, usually near the bead.

The specific requirements for the DOT code are outlined in the Federal Motor Vehicle Safety Standards, including 49 CFR Part 574, which governs tire identification and recordkeeping. The code acts as a fingerprint for the tire, linking it to the manufacturer and production details. This code is also essential for tire registration, which helps manufacturers notify you about safety recalls.

Where to find it

The DOT code is on the sidewall, often on the opposite side from the tire size and load markings. On many tires, it appears only on one side of the tire, so you may need to crawl under the vehicle or check both sides if you're looking at a mounted tire.

The code is usually a combination of letters and numbers, starting with the letters DOT. Once you locate it, you can read the entire sequence to get information about the tire's origin and age. If the code is worn or hard to read, use a flashlight or clean the sidewall with a damp cloth.

Reading the date code

The last portion of the DOT code is the date code. It gives you the week and year the tire was manufactured. This is the most useful part of the code for anyone buying tires, because it tells you how old the tire is, even if it looks brand new. Tires are made from rubber compounds that age over time, regardless of tread depth.

The date code is typically a four-digit number at the end of the sequence. The first two digits represent the week of the year (from 01 to 52), and the last two digits represent the year. For example, a code ending in 2319 indicates the 23rd week of 2019. Knowing this format lets you quickly determine the tire's age.

When you're about to buy a tire, ask the seller to read you the date code, or check it yourself on the sidewall. A tire that has been sitting in a warehouse for several years may not perform as well as a fresh one. The date code is a critical piece of information for making a smart purchase.

What the rest of the code means

The characters before the date code identify the manufacturer and the specific plant where the tire was built. The U.S. Department of Transportation assigns plant codes to each manufacturing facility. The code then continues with information about tire size and type, as defined by the manufacturer.

While you don't need to decode every letter, the presence of a complete DOT code confirms the tire is legal for highway use in the United States. For more details on sidewall markings, see our guide on tire sidewall markings.

It's worth noting that some tires also carry a separate code for retreads, which is governed by different standards. Retreaded tires must retain the original casing DOT symbol and plant code, as specified in the federal regulations for retreaded tires.

Other markings on the sidewall

Besides the DOT code, you'll see other markings that matter for buying and maintenance. The size designation, such as P225/50R17, tells you the tire's dimensions. The load index and speed symbol indicate the tire's load capacity and speed capability. Construction information like "RADIAL" tells you the ply arrangement.

The Uniform Tire Quality Grading (UTQG) system gives you treadwear, traction, and temperature grades. Understanding these helps you choose a tire that matches your vehicle and driving needs. These grades are molded into the sidewall according to federal regulations and offer a basis for comparing different tire models.

• Size designation: explains the tire's width, aspect ratio, and wheel diameter.
• Load index: tells you how much weight each tire can carry.
• Speed rating: shows the maximum safe speed for the tire.
• Construction type: indicates radial or bias ply structure.
• Treadwear and traction grades: part of the UTQG system that rates expected durability and grip.

Why the date code matters

The date code matters because tires degrade with age. Even if a tire has plenty of tread, the rubber can harden and lose grip, especially after many years. When you're buying tires, always check that the date code is recent. For specialized or low-volume tires, you may encounter "old stock" that's been sitting for a while.

If a seller can't show you a fresh date code, consider choosing a different tire. The same applies when you're inspecting a used vehicle or an emergency spare. Regular inspection and understanding tire age are key to safe driving, as covered in our tire replacement guidelines and tire store and inspect articles.

Many tire industry organizations, such as the Tire Industry Association, recommend replacing tires that are more than six years old regardless of tread depth. While specific age recommendations can vary, the general principle is that tires deteriorate over time, and a fresh date code is always preferable.

Tire registration and the DOT code

The DOT code is also used to register your tires with the manufacturer. This registration helps manufacturers notify you about recalls or safety issues. Many tire dealers offer registration at the point of sale, and you can also register on the manufacturer's website. The Tire Industry Association promotes tire registration as part of its safety campaigns.

If you don't register, you might miss an important recall notice. Keep a record of the DOT codes from your tires, and check for any recall announcements periodically. The U.S. Tire Manufacturers Association also provides resources to help consumers understand tire safety and maintenance.

What to pick for your use

Questions

What does DOT stand for?

DOT stands for Department of Transportation, the agency that regulates tire safety in the United States. The DOT symbol on a tire indicates that the tire complies with federal safety standards and is part of the tire identification system.

Where is the DOT code located?

It's molded onto the sidewall, usually near the bead. It may be on only one side of the tire, so check both sides if necessary. If the code is hard to read, clean the sidewall with a cloth and good lighting.

How can I tell the age of a tire from the DOT code?

The last four characters represent the week and year of manufacture. For example, a code ending in 4524 means the 45th week of 2024. A newer date is generally better, so always verify it before purchasing.

Is the DOT code the same as the tire size?

No. The DOT code is an identifier for manufacturing and recall purposes, while the size, load index, and speed rating are separate markings on the sidewall. Each serves a different function.

Do all tires have a DOT code?

Tires sold in the United States must have a DOT code to certify compliance with federal safety standards. This applies to new tires, retreads, and even temporary spares.

Can I register my tires using the DOT code?

Yes, the DOT code is used for tire registration so manufacturers can contact you about recalls. Registering your tires is a simple safety step that can be done at the dealer or online.