Free DOT Tire Age Calculator

The last group in the DOT stamp is the week and year. Age is a safety conversation, not a law.

Example: 3521 means the 35th week of 2021. If you only see three digits, the tire is from before the year 2000.

Where to find the DOT date code
DOT 35213521week · year
  • Look for the letters DOT on the sidewall. The group that matters is the last four digits of that series.
  • The first two are the week and the last two the year: 3521 is week 35 of 2021.
  • Many tires carry the full code on one sidewall only. If you cannot find it, check the inner side.
  • Three-digit codes predate the year 2000 and cannot pin down the decade with certainty.

What it does

Reads WWYY (after 2000) or the older 3-digit WWY code. Reports week, year, age, and conservative industry guidance.

How to use it

On the sidewall, find DOT. The date is the last 4 digits (3521 = week 35 of 2021). Sometimes it is only on the inside sidewall — crawl under or roll the tire.

How to read the result

NHTSA does not set a drop-dead age. Many manufacturers tell you to inspect at about 6 years and replace by about 10 years from the week of manufacture, even with tread left. A 3-digit code is pre-2000 and the decade is ambiguous — we will not guess 1988 vs 1998.

What this does not calculate

We decode the stamp. We cannot see dry rot, belts, or whether the tire was stored in the sun. A 4-year-old tire can still be unsafe if damaged.

Not a legal inspection and not a recall check.

Questions

Is there a US law that tires expire at 6 years?
No federal expiration date. Some states and fleets set their own rules. The 6/10-year figures are manufacturer and safety-advocate guidance.
Why is the code only on one side?
By rule it must appear on one sidewall. Shops often mount that side inward. Check both sides.

Related tools

Estimate — not a fitment approval.

Free DOT Tire Age Calculator