Tire Age Calculator — Check Your DOT Date Code

How to read a tire DOT date code

Every tire sold for road use carries a DOT code stamped into the sidewall by the manufacturer. The last four digits of that code tell you exactly when the tire was built. This four-digit block is written in WWYY format:

The first two digits are the week of the year (01 to 53) and the last two digits are the year. So 0125 is the first week of 2025, and 5223 is the 52nd week of 2023. Tires manufactured before the year 2000 used an older three-digit code; if you see only three digits, the tire is over 25 years old and should be replaced immediately.

Where to find the code

Look on the tire sidewall for the letters DOT followed by a series of numbers and letters. On many tires the complete date code only appears on the inner sidewall (the side facing the vehicle), so you may need to look on both sides or turn the wheel.

Why tire age matters

Rubber is an organic material that degrades with time, independent of how much you drive. Heat, sunlight, oxygen, and ozone slowly harden the compound and can cause tiny cracks to form in the sidewall and tread grooves. An aged tire can fail suddenly even if it still has plenty of tread depth and looks almost new — which is why a tire that has spent years in storage, on a spare wheel, or on a low-mileage vehicle can still be dangerous.

Checking the date code is the only reliable way to know a tire's true age. Tread depth tells you about wear; the DOT code tells you about age. Both need to be safe.

When should you replace a tire?

There is no single legal expiry date for tires, but widely cited guidance from vehicle and tire manufacturers and road-safety bodies is:

• Have tires inspected by a professional once they reach 5 years of age.
• Many car makers recommend replacing tires at 6 years regardless of tread.
• Most tire manufacturers state that tires should be replaced 10 years after the date of manufacture at the very latest, even if unused.

Replace a tire sooner if you see sidewall cracking, bulges, uneven wear, or tread below the legal minimum. Always follow the specific guidance in your vehicle owner's manual and from the tire manufacturer.

Frequently asked questions

Where do I find the DOT date code on my tire?

On the sidewall, after the letters "DOT". The last four digits are the date code (WWYY). On some tires the full code is only on the inner sidewall facing the vehicle.

How old is too old for a tire?

Many manufacturers recommend replacement at 6 to 10 years of age regardless of tread, because rubber degrades over time. Follow your vehicle and tire manufacturer guidance.

Does tire age matter if the tread looks fine?

Yes. A tire with plenty of tread can still be unsafe if the rubber has aged, hardened, or cracked. Age and tread depth are separate checks.

What does a 3-digit DOT code mean?

Tires made before the year 2000 used a 3-digit date code. Those tires are decades old and should not be in service. This calculator is built for the modern 4-digit WWYY format.