EN

Tire age calculator (DOT date code)

This tire age calculator decodes the DOT date code on the sidewall. Enter the whole DOT number or just the last four digits: the first two are the week, the last two the year, so 4521 means week 45 of 2021. You get the exact production week (Sunday to Saturday) and how old the tire is today.

Source: 49 CFR 574.5, 49 CFR § 574.5 Tire identification requirements, (b)(3) date code (LII Cornell, read 09.10.2026). Updated: .

the four digits at the end, often inside an oval
My ToolboxYour inputs are saved in this browser only.

Result

Date of manufacture
week 45 of 2021 · 4 years and 11 months old
Details
ItemValue
Date code45 = week, 21 = year
Week of manufactureweek 45 of 2021
Dates7 November 2021 – 13 November 2021
Tire age today4 years and 11 months
Assessmentunder 5 years – Continental says a properly stored, unused tire can be sold as new for up to 5 years after production
Age says nothing about tread depth or damage. Check tread depth, cracks, bulges and how the tire was stored. The full DOT number is often only on one sidewall.

How it is calculated

The last four digits of the DOT code are the date of manufacture: the first two are the week, the last two the year. 4521 means week 45 of 2021 – the week of November 7 to 13, 2021.

How to read the DOT date code

The DOT number (Tire Identification Number) is made up of a plant code, a manufacturer’s code and, at the end, the four-digit date code. Under 49 CFR § 574.5, week 01 is the first full calendar week of the year and each week runs from Sunday to Saturday; the last week of a year may include up to six days of the next year.

CodeWeekDates
0109week 1 of 2009January 4–10, 2009
1219week 12 of 2019March 24–30, 2019
4521week 45 of 2021November 7–13, 2021
3524week 35 of 2024September 1–7, 2024
5323week 53 of 2023December 31, 2023 – January 6, 2024

A code such as 5324 is invalid, because 2024 has only 52 weeks under this count. The 0109 example is the one given in the regulation. Tires made before 2000 have a three-digit code (week plus the last digit of the year) and are now over 25 years old.

How old is too old for tires?

US federal law sets no maximum age. Continental gives two limits: a properly stored, unused tire can be sold as new for up to 5 years after its production date, and tires older than 10 years should be replaced. Between 5 and 10 years, have them checked regularly for cracking and hardening. To compare sizes, use the tire size calculator; for braking, the stopping distance calculator.

Limits

The calculator counts the age from the Sunday of the production week to today. It does not judge the condition of the tire: tread depth, cracks, bulges, storage and mileage all decide whether a tire is still safe.

Frequently asked questions

Where is the DOT code on a tire?

On the sidewall after the letters “DOT”. The date is the last four digits, often inside an oval. The full number is sometimes only on one side of the tire.

What does DOT 4521 mean?

The tire was made in week 45 of 2021, between November 7 and 13, 2021.

How old can new tires be when I buy them?

Continental says a properly stored, unused tire can be sold as new for up to 5 years after production.

At what age should tires be replaced?

Continental recommends replacing tires older than 10 years regardless of tread depth. There is no federal age limit.

What does a three-digit DOT date code mean?

Tires made before 2000 used three digits: two for the week and one for the year. They are over 25 years old and should not be used.

How are tire weeks counted?

Week 01 is the first full Sunday-to-Saturday week of the year (49 CFR § 574.5). In 2009, for example, it ran from January 4 to 10.

Sources and legal basis

As of: · Editorial policy

Related tools