How to Tell Age of Car Tires | Read the DOT Date Code

A car tire’s age is found in its DOT code which ends with four digits showing the week and year it was made, like “1023” for the 10th week of 2023.

Most drivers never look at their tire’s birth date, and that’s a problem. Rubber hardens and cracks over time, even on tires with plenty of tread left. A tire that looks fine can blow out at highway speed simply because it is too old. The quickest way to tell if yours are still road-safe is to find the tiny code stamped on the sidewall and read its last four numbers. Here is how to decode that code, when to replace, and what catches most people off guard.

Where to Find the DOT Code on a Tire

The code starts with the letters “DOT” and runs along the lower part of the tire’s sidewall near the rim. On most passenger cars the full code—including the date section—is on only one side of the tire, usually the outer side facing away from the vehicle. If you look from outside the car and see “DOT” followed by letters and numbers but no four-digit date, the date code is on the inner sidewall. You will need to crawl under the vehicle, turn the steering wheel fully, or remove the tire to read it. Do not skip this step: a tire’s true age is often invisible from the curb.

How to Decode the Tire Date

For any tire made after January 1, 2000, the last four digits of the DOT code are the date. The first two digits are the week (01 through 52), and the last two digits are the year. “3020” means the 30th week of 2020. “1023” means the 10th week of 2023. If the tire is new enough to still smell like rubber but the code shows “4519,” it sat on a shelf or a lot for five years before it ever touched the road. Always check the date before buying; counter-intuitively a “new” tire can be several years old.

For tires made before 2000, the date code uses three digits. The first two are the week; the third is the year within the decade. A “439” could be the 43rd week of 1989 or 1979. A triangle symbol stamped after the three digits confirms the 1990s. Any tire with a three-digit code is now well over a decade old. It should be replaced immediately regardless of how its tread looks.

When Should You Replace Tires by Age?

The United States has no federal expiration date for tires, but the general recommendation is straightforward. Tires should be replaced between five and six years from the date of manufacture, even if they have never been used. Some automakers are more strict: Ford, Nissan, and Mercedes-Benz specify replacement at six years regardless of tread condition. Tire manufacturers like Continental and Michelin set the limit at ten years with annual inspections required after the fifth year. After year seven, the risk of sudden failure increases sharply because the rubber compound loses its elasticity and tiny cracks form inside the structure where you cannot see them.

In practice, whether you should buy a new set or can wait another year depends largely on the tires you have now. Our tested roundup of the best car tires compares the top models for mile-per-dollar value if you are already in the market.

Common Mistakes That Leave Tires Unsafe

The single most common error is checking the wrong sidewall and concluding there is no date code. Search both sides of every tire, including the spare. Spare tires age just as fast as the four on the ground and are often the oldest tire on a vehicle because they are never rotated or worn down. Another frequent blind spot is buying “new” stock tires from a discount shop without checking the DOT code. A tire with a four-year-old date code is not new; ask for a fresher one or walk away. For pre-2000 tires without a triangle symbol, the decade is ambiguous; err on the side of replacing any tire you cannot confidently date.