The DOT code on your tire's sidewall tells you exactly when it was manufactured
Every tire sold in the United States has a Department of Transportation (DOT) code stamped into the rubber on the sidewall. The last four digits of this code are the tire's birth date. The first two digits represent the week of manufacture (01 through 53), and the last two digits represent the year. A tire marked 3519 was made in the 35th week of 2019.
You do not need any tools to read this code — just locate the sidewall marking that begins with "DOT" and look at the final four numbers. This is the fastest way to know whether a tire is new, middle-aged, or old enough to replace regardless of tread depth.
Tire age matters because rubber degrades over time, even when a vehicle sits unused. The rubber compounds harden and lose flexibility, which reduces grip and increases the risk of blowouts. Most tire manufacturers recommend replacement at ten years from the date of manufacture, and many insurance companies and safety organizations suggest replacing tires at six years if they see heavy use or live in hot climates.
Key Takeaways
- The DOT code's last four digits show the week and year a tire was made — for example, 2520 means week 25 of 2020.
- Tires degrade with age even if they look fine, so a tire older than six to ten years should be replaced even if the tread is still deep.
- You can check all four tires in under a minute by walking around your vehicle and reading the sidewall of each one.
- A tire that is older than the vehicle itself may have been a used or returned tire, which carries unknown history and risk.
Where to find the DOT code on your tire
The DOT code appears on the sidewall — the vertical part of the tire between the tread and the rim. On most vehicles, you can see it without removing the tire. Crouch down or kneel beside each wheel and look for a series of letters and numbers that starts with "DOT." The code is typically 10 to 13 characters long.
The code may wrap around the sidewall, so if you do not see it when ready, trace your finger along the rubber. On some tires, the DOT code appears on both sidewalls; on others, only one side. If you cannot read it clearly in daylight, use your phone's flashlight or a small flashlight to illuminate the sidewall.
If your vehicle is lifted or has oversized wheels, the sidewall may be harder to reach. In that case, you can also check your vehicle's maintenance records or contact the tire shop where the tires were installed — they will have the manufacture dates on file.
How to read the four-digit date code
Once you locate the DOT code, focus on the last four digits. Ignore everything before them. The format is always WWYY, where WW is the week number and YY is the year.
Weeks run from 01 (first week of January) through 53 (the final week of December). Years are shown as single digits: a tire marked 2518 was made in week 25 of 2018. A tire marked 0523 was made in week 05 of 2023. If you see 4924, that tire was made in week 49 of 2024.
To find the exact date, you can count forward from January 1st, or use an online tire date decoder — many tire retailers and manufacturer websites offer free calculators where you enter the four digits and get the specific week and year. This step is optional; knowing the year alone is usually enough to decide whether replacement is necessary.
Why tire age matters more than you might think
A tire with 8/32 of an inch of tread remaining is still legal to drive on in all 50 states, but a tire that is ten years old should be replaced even if the tread is 10/32 of an inch deep. This is because the rubber itself has aged. Sunlight, heat, ozone, and the flexing of the tire during driving all cause the rubber compounds to break down.
Older tires are more prone to sidewall cracking, which can lead to sudden deflation or blowout. They also lose their grip in wet conditions, even if the tread pattern looks fine. A tire that has been sitting in a garage for five years without being driven is still aging — storage does not stop the clock.
Hot climates accelerate aging. A tire in Arizona or Florida may need replacement sooner than the same tire in Minnesota. If you live in a warm region or park your vehicle in direct sunlight regularly, check your tire dates more often and consider replacing them at six years rather than waiting until ten.
What to do if your tires are older than six years
If you find that one or more tires are older than six years, schedule an inspection with a tire shop or mechanic. They can assess the tire's condition — looking for cracks, bulges, or other signs of aging — and recommend whether replacement is necessary now or can wait a few more months.
If a tire is older than ten years, most shops will recommend replacement regardless of tread depth. Some shops will refuse to repair an old tire, even if the damage is minor, because the risk of failure is too high.
If all four tires are old, you will need to replace all four at once for safety and to maintain even traction. If only one or two are old, you may be able to replace just those and keep the newer ones, though some shops prefer to replace tires in pairs (front or rear) to maintain balanced handling.
Checking tire age when buying a used vehicle
Before you buy a used car, check the tire dates. A vehicle with tires that are already five or six years old means you will need to budget for replacement soon after purchase. If the tires are eight years or older, factor in the cost of new tires as part of your negotiation.
A used vehicle with brand-new tires (less than a year old) is a good sign — it suggests the previous owner maintained the vehicle. Conversely, a used vehicle with very old tires may indicate neglect or that the vehicle sat unused for a long time.
If a dealer or private seller claims the tires are new but the DOT code shows they are several years old, that is a red flag. It means the tires were either returned to the manufacturer, sold as overstock, or stored for an extended period before installation. These tires may have unknown history and carry higher risk.
Frequently Asked Questions
Can I drive on a tire that is eight years old if the tread is still good?
You can, legally, but it is not recommended. Tire age affects safety more than tread depth alone. A tire that is eight years old has degraded rubber that loses grip in wet conditions and is more prone to failure, even if the tread looks fine. Most safety experts suggest replacement at six to ten years from manufacture, regardless of tread depth.
Does the date code tell me when the tire was installed on my vehicle?
No. The DOT code shows when the tire was manufactured, not when it was put on your car. A tire could have been made in 2020, stored for two years, and installed in 2022. If you need to know the installation date, check your vehicle's service records or ask the shop where the tires were installed.
What if I cannot find the DOT code on my tire?
The code is always there — it is required by law. It may be on the inner sidewall (the side facing the vehicle body) rather than the outer sidewall. If you still cannot locate it, use a flashlight and trace the entire sidewall carefully. If the code is worn away or illegible, a tire shop can help you identify the tire's age or recommend replacement based on its condition.
Do tires age faster if the vehicle is parked and not driven?
Yes, in a sense. A parked vehicle's tires still age due to sunlight, temperature changes, and ozone exposure. However, tires on a regularly driven vehicle may wear out faster in terms of tread loss. Age and wear are separate concerns — a tire can be old and have deep tread, or new and worn flat.
Should I replace all four tires at the same time if only one is old?
Not necessarily. If three tires are relatively new and one is old, you can replace just the old one if its tread depth is similar to the others. However, some shops recommend replacing tires in pairs (front or rear) to maintain balanced handling and traction. Ask your mechanic for their recommendation based on your vehicle and driving conditions.