How to read a tire date code
The date code is the last 4 digits of the Tire Identification Number (TIN), the code that starts with DOT on the sidewall. The first two digits are the week, the last two are the year. 2423 means week 24 of 2023.
The federal rule, 49 CFR 574.5, defines week 01 as the first full calendar week of the year, running Sunday to Saturday. The rule's own example: 0109 is the week from January 4 to January 10, 2009. So week 01 does not always start on January 1, and it is not the ISO week some calendars show. This calculator follows the rule:
week start = first Sunday of the year + 7 × (week − 1) daysWorked example, 2423: January 1, 2023 was a Sunday, so week 01 ran January 1 to 7. Week 24 starts 7 × 23 = 161 days later, on Sunday, June 11, 2023, and ends on Saturday, June 17. On September 30, 2026 that tire is 3 years and 3 months old (1,207 days), counted from June 11.
How the age is counted
The date code gives a week, not a day, so the calculator counts from the Sunday that starts that week. The real age can be up to 6 days less than shown. The result is given in whole years and months, plus the number of days, and it updates to today's date each time you open the page.
What the DOT code says
After the letters DOT, a current TIN has 13 symbols in three parts:
- Plant code: 3 symbols for the factory. Older tires have 2. Plants that had a 2-symbol code were allowed to keep it until April 13, 2025.
- Manufacturer's code: 6 symbols.
- Date code: 4 digits, week then year. It may be laser etched.
Retreaded tires carry a TIN of 7 symbols with an R mark. If you do not see the code, look at the other sidewall too. You can paste the whole code into the calculator: it reads the last 4 digits.
3-digit codes: tires made before 2000
Before 2000 the date code had 3 digits: two for the week and one for the last digit of the year. 429 is week 42 of a year ending in 9. The code does not say which decade, so the calculator shows the minimum age: in 2026 such a tire is at least 26 years old.
How old is too old?
Age matters, not only tread depth. This page does not set an age limit. Vehicle makers and tire makers publish their own age recommendations: check your owner's manual and the tire maker's guidance for your tires.
Tire DOT number lookup and recalls
This page only decodes the date. Recall checks by TIN are done on NHTSA's official site, nhtsa.gov/recalls. Nothing you type here is sent anywhere.
Checking a set
Tires on one vehicle can have different dates, for example after a single tire was replaced. Enter the code from each tire in the set checker to see which one is oldest and how far apart they are.
Questions
How do I read a tire date code?
Find the code that starts with DOT on the sidewall and read its last 4 digits: week, then year. 2423 is week 24 of 2023, the week from Sunday, June 11 to Saturday, June 17, 2023.
How old are my tires?
Enter the last 4 digits above. A tire coded 2423 was 3 years and 3 months old on September 30, 2026, counted from the first day of its week.
What does a 3-digit tire date code mean?
The tire was made before 2000. The digits are the week and the last digit of the year: 429 is week 42 of a year ending in 9, so in 2026 the tire is at least 26 years old.
Can I look up a tire DOT number for recalls?
Recall checks by TIN are done on NHTSA's official site, nhtsa.gov/recalls. This page only decodes the date.
How many years can a tire be used?
This page does not give an age limit. Vehicle makers and tire makers publish their own age recommendations: check your owner's manual and the tire maker.