Tire Age Calculator
Use this tire age calculator to decode the DOT date code stamped on your tire’s sidewall, find the exact manufacture week and year, and calculate chronological tire age.
Look for the characters following DOT on your sidewall. The date code is strictly the last 4 digits (e.g. in DOT Y9 AB 1234 2322, enter 2322).
Manufacture Date & Service Age
Manufacturing Week: Jun 5 – Jun 11, 2022
Age alone does not determine serviceability. Continue routine inspection and follow the applicable tire and vehicle manufacturer guidance.
Calculations use documented geometric and mathematical relationships, with tire-industry standards and manufacturer specifications referenced where relevant.
How the Tire Age Calculator Works
Every highway-certified tire sold in the United States carries a standardized Department of Transportation (DOT) Tire Identification Number (TIN) molded into its sidewall. The final segment of this sequence encodes the manufacturing week and calendar year under federal regulation 49 CFR § 574.5. The Tire Age Calculator decodes this numeric stamp to calculate the elapsed chronological time since manufacture.
- Locate the DOT TIN: Find the alphanumeric string on your tire sidewall starting with the letters "DOT".
- Identify the Final 4 Digits: Look for the final four numeric digits of the complete TIN. They are often molded in a small oval or separate date-code area at the end of the TIN sequence (e.g.
2322). - Extract the Manufacture Week: The first two digits (
23) denote the calendar week of manufacture (weeks 01 through 53, running Sunday through Saturday). - Extract the Manufacture Year: The final two digits (
22) represent the two-digit year of the 21st century (2022). - Compute Chronological Age: Calculate the elapsed years and months between the manufacturing week and today's date.
Worked Example: Decoding Tire Date Code 2322
• Week Digits (First Two): 23 → 23rd calendar week of 2022 (Sunday June 5 through Saturday June 11, 2022)
• Year Digits (Last Two): 22 → Calendar year 2022
• Manufacturing Week: June 5–11, 2022 (Week 23)
• Calculated Age: approximately 4 years, 3 months (about 4.2 years old)
Michelin recommends annual professional inspection after five years of service and precautionary replacement at ten years from manufacture. Continental recommends removing tires more than ten years old from service. Vehicle-manufacturer guidance may differ.
Where Is the DOT Date Code on a Tire?
Under federal motor vehicle safety regulations (49 CFR § 574.5), the Tire Identification Number (TIN) is molded into the lower sidewall area near the wheel rim.
Federal rules permit manufacturers to stamp the complete TIN—including the 4-digit date code—on only one of the two sidewalls. The opposite sidewall often contains a partial TIN showing only the plant code and size code without the date digits. If the date code is not visible on the outward-facing sidewall, inspect the inward-facing sidewall under the vehicle.
How to Read a 4-Digit DOT Tire Date Code
What Do 3-Digit Tire Date Codes Mean?
Tires manufactured prior to the year 2000 used a 3-digit date code format where the first two digits represented the week (01–53) and the third digit represented the single-digit year of that decade.
Because single-digit years lack a century indicator, code 346 could denote the 34th week of 1986 or 1976. During the 1990s, many manufacturers added a small triangle symbol (△) following the three digits to distinguish 1990s production (e.g. 346△ = 34th week of 1996).
A genuine 3-digit date code indicates manufacture before 2000. That makes the tire more than 25 years old today and far beyond the age limits commonly recommended by tire and vehicle manufacturers. Do not rely on tread appearance alone; follow the applicable tire and vehicle manufacturer guidance before any continued road use.
Is Tire Age the Same as Tire Service Life?
Chronological age and physical service life represent two entirely distinct dimensions of tire health:
1. Chronological Age (Chemical Aging)
Rubber is an organic polymer that degrades through oxidation, ultraviolet exposure, ozone, and thermal cycles. Over time, anti-ozonants deplete, rubber compounds harden, and structural adhesives between steel belts and carcass plies lose flexibility, increasing the risk of internal degradation even on unused spare tires.
2. Tread Wear (Mechanical Life)
Tread depth and chronological age measure different things. A tire may require replacement because its tread has reached the applicable legal or manufacturer limit even if it is relatively young, while an older tire may require replacement or professional inspection despite substantial remaining tread. Follow the applicable tread-depth requirements and tire/vehicle manufacturer age guidance.
Industry & Manufacturer Tire Age Guidelines
Tire service life and replacement recommendations differ across standards organizations, tire manufacturers, and vehicle OEMs:
NHTSA notes that some vehicle and tire manufacturers recommend replacing tires that are six to ten years old regardless of treadwear. NHTSA itself does not impose one universal age-based federal replacement mandate, but emphasizes proper inflation pressure, alignment, and physical condition checks.
Michelin recommends that after five years of service, tires should be thoroughly inspected at least annually by a trained tire professional. Michelin also recommends replacement at ten years from manufacture as a precaution, regardless of remaining tread depth or apparent condition.
Continental advises that all tires, including spare tires, made more than ten years ago should be removed from service and replaced. Continental also notes that vehicle manufacturers may specify a different chronological replacement age.
Some vehicle manufacturers specify their own age-based replacement intervals (such as six years) in vehicle owner manuals. Always consult and follow the applicable vehicle manufacturer guidance.
USTMA emphasizes that chronological age is an important inspection factor alongside proper inflation maintenance, alignment, damage inspection, and physical condition.
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Frequently Asked Questions
References & Authoritative Standards
- Electronic Code of Federal Regulations (eCFR) – 49 CFR Part 574: Tire Identification and Recordkeeping. National Highway Traffic Safety Administration (NHTSA) regulations governing Tire Identification Number (TIN) composition, Sunday–Saturday week definition, and date stamping.
- U.S. Tire Manufacturers Association (USTMA) – Tire Replacement & Service Guidelines. Industry consensus guidelines on passenger and light truck tire service life, aging, and inspection protocols.
- NHTSA – Tire Safety & Aging Research. U.S. Department of Transportation safety findings regarding tire rubber thermo-oxidative degradation and service recommendations.
- Michelin North America – When to Replace Tires & How to Read Date Codes. Manufacturer policy on 5-year annual inspection and 10-year precautionary service replacement.
- Continental Tire – Tire Age & Replacement. Manufacturer technical bulletin recommending removal from service and replacement of all tires manufactured more than 10 years earlier.