How Old Are My Tires? Reading the DOT Date Code
Last updated . Sources were opened on Oct 31, 2026, and are linked in the text.
Tires sold in the U.S. carry their build date on the sidewall, as part of a federally required identification number. It takes a minute to find once you know where to look. Here is how to read it, and what the tire makers and NHTSA say about how old is too old.
Free tool: Tire Check reads the date code for each of your tires, works out the age, and adds tread and damage checks, with a red, yellow or green result. It runs in your browser, with no sign-up.
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Where to find the date code
- Look on the sidewall for the letters "DOT" followed by a string of letters and numbers. That is the tire identification number (TIN).
- The date code is the last group of four digits at the end of that number.
- Check both sides. Federal rules only require the full number on one sidewall, so it may be facing the car (49 CFR 574.5; NHTSA). On a mounted tire you may need a flashlight, or to look from under the car.
How to read the four digits
The first two digits are the week of the year and the last two are the year (49 CFR 574.5).
| Code | Means | Source example |
|---|---|---|
| 0109 | First full calendar week of 2009 (the week of Jan 4 to Jan 10, 2009) | 49 CFR 574.5 |
| 0308 | Third week of 2008 | NHTSA |
| 3520 | 35th week of 2020 | Michelin |
| 2406 | 24th week of 2006 | Bridgestone safety manual |
Week 01 is the first full Sunday-to-Saturday week of the year, so week numbers line up only roughly with months. Week 24, for example, falls in June. For working out a tire's age, the year is what matters most.
Three digits instead of four? Tires made before 2000 used a three-digit code. Bridgestone's example: a code ending in 329 was likely made in the 32nd week of 1999, but possibly 1989 (Bridgestone safety manual). Either way, that tire is more than 25 years old.
How old is too old?
We couldn't find a federal rule that sets a maximum tire age. The guidance comes from tire and vehicle makers:
- Michelin recommends a thorough inspection by a tire professional at least once a year after five years of service, and replacing tires 10 years after the date of manufacture regardless of tread depth or how they look. That includes spares (Michelin).
- Bridgestone recommends a professional inspection after five years of use, with the spare inspected at the same time, and replacing all tires, spares included, made more than 10 years earlier, even if they look usable (Bridgestone).
- NHTSA says some vehicle and tire makers recommend replacing tires that are six to 10 years old, regardless of tread wear (NHTSA). Your owner's manual may give your vehicle maker's own figure, and that comes first.
So, roughly: under five years, keep up the usual monthly checks. From five years, have a professional look at them each year. At 10 years, replace them. Ten years is a ceiling, not a target. Most tires wear out well before then.
Who should pay the most attention
NHTSA says most drivers wear out their tread before age becomes an issue. It names the people more at risk from tire aging: owners of RVs, 15-passenger vans, collector cars and other vehicles that aren't driven regularly, and anyone with low annual mileage. Sun, a warm climate and poor storage add to it, and NHTSA calls tire aging a greater concern in the southern Sun Belt states. You can't see tire aging just by looking (NHTSA).
- RVs, trailers and campers: these often sit for months and rack up few miles, so the tread can look nearly new on a tire that is well past the age guidance. Check the date code on every tire, including the spare.
- The spare: NHTSA notes that spares age because they're seldom replaced (NHTSA). Michelin says a compact spare that has never been used still ages from its date code, and the 10-year guideline applies to it too (Michelin).
- Used cars: the tires may be older than they look. Read all the date codes before you buy.
- "New" tires from a shop: the date code tells you when a tire was made, not when it was sold. If it matters to you, ask to see the codes before the tires are mounted.
Storing tires to slow aging
Bridgestone says to store tires indoors in a cool, dry place, away from heat sources such as hot pipes, motors and generators, and not to let water collect inside them. It says to avoid temperatures below freezing and above 100°F (38°C) (Bridgestone).
Age is only one check
A young tire can still be worn out or damaged. Read Do I need new tires? for tread depth, the penny and quarter tests, and damage you shouldn't drive on, or run all of it at once in Tire Check. To check for recalls, search NHTSA's recall site, or USTMA's lookup by the full tire identification number (it covers tires made by USTMA member companies since 2000).
This guide is general information, not a substitute for an inspection by a tire professional.
Common questions
Where is the date code on a tire?
On the sidewall, at the end of the tire identification number that starts with DOT. The full number is only required on one side, so check both sides of the tire.
How do I read a tire date code like 2419?
The first two digits are the week and the last two are the year, so 2419 means the 24th week of 2019.
How many years are tires good for?
Michelin and Bridgestone recommend a professional inspection after five years (Michelin says yearly) and replacing tires 10 years after manufacture, spares included. NHTSA says some vehicle and tire makers recommend replacement at six to 10 years. Check your owner's manual.
What does a three-digit date code mean?
The tire was made before 2000. Bridgestone's example: 329 was likely made in the 32nd week of 1999, but possibly 1989. Such a tire is well past the 10-year guidance.