Tire age: read the DOT date code
Type the last four digits of each tire's DOT code, spare included. The calculator gives the week and year each tire was made and its age today. No age is marked too old: tire makers disagree, so the guidance table names who says what.
Assumptions behind the numbers
- NHTSA reads the last four digits of the Tire Identification Number as the week and the year of manufacture: 2321 is the 23rd week of 2021.
- The federal rule for the code (49 CFR 574.5) makes week 01 the first full calendar week of the year, Sunday through Saturday. Age is counted from the Sunday that starts the week, so it can be off by up to six days.
- A code that is not four digits, or a week number above 53, is reported and skipped. This calculator reads only the four-digit week-and-year code the current rule describes.
- No age is marked too old. Guidance ranges from 6 years on one Ford page to 10 years for Michelin and Continental, and USTMA says it knows of no data for a fixed life. Follow the maker of your tires and your car.
Tire age guidance: who says what
There is no federal age limit for passenger car tires, and the sources do not agree. The table sets out each one with its conditions, so you can find the guidance that applies to your tires and your car. Follow the maker of your tires and the maker of your car; where they differ, ask the tire maker or a tire professional which applies. Ask the authority
| Source | What it says about age | Conditions |
|---|---|---|
| NHTSA (federal agency; TireWise) | Some vehicle and tire makers recommend replacing tires that are six to 10 years old. Aging cannot be seen by looking. | Lists low-mileage vehicles, warm climates and sunlight among the conditions linked with aging. |
| Michelin (tire maker; When Do I Need New Tires?) | A professional inspection at least once a year after 5 years of service; replace 10 years after the date of manufacture, spares included. | For original-equipment tires, follow the vehicle maker's advice. Age alone does not decide whether a tire is serviceable. |
| Continental (tire maker; Replacing tires) | Tires more than 10 years old, spares included, should be removed from service. | Says it knows of no technical data for a specific age, and that age matters. |
| USTMA (tire makers' trade association; Care and Service manual) | Not aware of scientific or technical data that sets a minimum or maximum service life. | Says a maker's age advice should not be read as a minimum life; tires, spare included, should be inspected by a professional periodically. |
| Ford (carmaker; Tire Replacement) | Replace every six years or when worn out, whichever comes first, spare included. | For Ford vehicles. Ford's other tire page (How often should I replace) gives condition signs and no age. |
Write each tire's code on Car facts, and the age you work out beside it. Tires explains how to read the code on the sidewall and what the spare needs.
The calculator gives an age, not a verdict. A tire's condition, damage, repairs and storage matter as well as its age, and only a tire professional can judge them. No age on this page is marked too old.