How to Read a Tire Date Code and Check Tire Age

Before you start

You only need the tire sidewall and enough light to read the raised lettering. The date code is part of the DOT serial stamped on one sidewall, so you may have to crouch near the wheel or turn the steering wheel for a clearer view. This check is done locally on the tire itself; no app, scan, or online lookup is required.

Step-by-step instructions

1) Park on a level surface and set the parking brake. If the code is not visible, turn the steering wheel or move the vehicle slightly so the sidewall faces you.

2) Look for the letters DOT followed by a series of characters. The full code can be 10 to 12 characters, but the part you need is the last four digits.

3) Find the final group of four numbers. These are usually pressed into the sidewall inside an oval or beside the other DOT characters.

4) Read the week and year from those four digits. For example, 3521 means the 35th week of 2021; 0423 means the 4th week of 2023. The first two digits are the week, and the last two digits are the year.

5) If the tire has only a three-digit group after DOT, it was made before 2000 and should be considered too old for service.

6) Note the code from each tire position if you are checking a whole vehicle. Tires of the same brand and model may still have different production weeks.

Check the output

A valid modern date code ends with four digits and gives you a week from 01 to 52 plus a year. The readable result should match a realistic production date, not a future date. Sidewall codes can be worn, partially hidden by dirt, or positioned on the inward-facing side, so clean the area only with a soft cloth and avoid scraping the rubber.

Common problems and next steps

If the last four digits are missing from the visible sidewall, check the opposite sidewall. The complete DOT code may only appear on one side. If you see a three-digit code or no code at all, the tire predates the current marking system or the stamp is damaged.

For a used car, compare the date codes with the vehicle age. Matching dates can support lower mileage or recent replacement, but they do not prove the tires were installed on that date. Uneven production weeks between tires may simply mean one was replaced later.

For tire condition, use the date code as one input only. Aging depends on storage, exposure, load, and pressure, so a newer tire can still be damaged and an older tire may still require inspection. Do not treat the stamp as a guarantee of use or safety.