How to read a tire's DOT date
By Tagwell Auto · Last updated October 9, 2026
The short answer: find the code starting with DOT on the sidewall. The last four digits are the week and the year the tire was made. 2319 means the 23rd week of 2019.
Where to look
- Find the letters DOT on the sidewall, followed by a string of letters and numbers.
- Read the last four digits. The first two are the week (01 to 53). The last two are the year.
- If you only see a short code with no four digits at the end, the full code is on the other side of the tire.
A code that ends in three digits is from before the year 2000. That tire is far too old to drive on.
How old is too old
Rubber ages even when the tread looks fine. Sun, heat and time dry it out and it can crack or come apart.
| Tire age | What to do |
|---|---|
| Under 6 years | Check tread and condition as usual |
| 6 to 10 years | Have them inspected every year, and plan to replace them. Many tire and car makers say to replace at 6 |
| Over 10 years | Replace them, whatever the tread looks like. That includes the spare |
Check your owner's manual and the tire maker's advice, because recommendations differ.
Check the tread while you're there
- 2/32 of an inch is the legal minimum in most US states. At that depth a tire is worn out
- At 4/32, wet grip is already much worse. Start shopping
- The penny test: put a penny in the groove with Lincoln's head down. If you can see all of his head, the tread is at 2/32 or less
Buying tires or a used car
Check the date before you pay. A "new" tire can sit in a warehouse for years, and a low-mileage used car can still be on its original, aged tires. Trailers and RVs are the usual place old tires hide: they age out long before they wear out.
General guidance. Typical intervals, and your owner's manual wins. If a red warning light is on or the car drives differently, stop safely and get help.
Related: Read your tire's date code · Miles and maintenance in Tagwell Auto
Track this automatically in Tagwell Auto
In Tagwell Auto, type the four digits for each tire and it works out the age, warns you at 6 years, and tracks tread depth by position.
Questions
What do the last four digits of the DOT code mean?
The week and year the tire was made. 2319 is the 23rd week of 2019.
How old can tires be before they should be replaced?
Many makers recommend replacing tires at 6 years, and none later than 10 years, whatever the tread depth. Check your manual.
Do trailer and spare tires age too?
Yes. They often age out before they wear out, because they sit in the sun and are rarely driven.