Maintenance ScheduleTire age
How old is this tire?
Read the four-digit DOT code on the sidewall. The first two digits are the week, the last two the year.
Read the DOT date code
The last four digits of the code are the week and year.
Result
Enter the code
What the code means
A four-digit code is the week and year of manufacture: 2321 is week 23 of 2021. The code is molded into the sidewall, usually after the letters DOT. This calculator turns it into the week’s date range and the tire’s age today.
Three-digit codes were used before 2000. They are explained on the page but not dated, because the year is ambiguous.
What NHTSA says
NHTSA says you cannot detect tire aging simply by looking at a tire. Some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear. The last four digits of the DOT Tire Identification Number give the week and year the tire was made.
There is no single federal age limit for passenger tires. Follow the vehicle or tire maker’s guidance, and have the tire inspected for cuts, bulges, cracking and tread wear.
When to replace a tire
Replace a tire when the tread reaches the legal minimum, when there is a cut, bulge or cracking, or when the maker’s age guidance says so. Age is one part of the decision, not the whole of it. A tire that has plenty of tread but has been sitting in the sun can still be unsafe.
Tire age questions
Where is the DOT code on a tire?
On the sidewall, usually after the letters DOT. The last four digits are the week and year of manufacture. The code is only required on one side, so you may need to look under the car.
How old is too old for a tire?
There is no single legal age for passenger tires in the US. NHTSA says some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear. Follow the maker’s guidance and have the tire inspected.
Should I replace a tire with good tread because of its age?
Follow the vehicle or tire maker’s guidance. Age, tread, cracking, cuts and bulges all matter. A tire with good tread can still have aged rubber.
What does a three-digit code mean?
Three-digit codes were used before 2000. They do not give a year this calculator can date. Treat the tire as old and have a specialist check it.
Does the UK 10-year rule apply in the US?
No. The UK rule is for heavy vehicles in Great Britain. In the US, NHTSA’s guidance and the tire maker’s recommendations are the ones to follow.
Sources
The US age guidance and the DOT code explanation are checked against NHTSA. This page is general information, not a tire inspection.
- Tire safety ratings and awareness. NHTSA (US Department of Transportation).US guidance of six to 10 years, and how to read the DOT date code. Checked 6 November 2026.