Quick Answer
- The last 4 digits of the DOT code are the date code: 1923 means week 19 of 2023, which began on Sunday, May 7, 2023.
- A 3-digit date code means the tire was made before 2000, and Bridgestone says it should be replaced due to age.
- NHTSA says some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear.
Tire Age
3yr
Manufactured
Week 19
2023
Week begins May 7, 2023
Age
3y 5m
41 months total
Under 6 years old. No age limit in the manuals we read applies yet. Keep checking pressure, tread and sidewall condition.
NHTSA: some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear. Age is calculated from the date code to today's date.
Get a plain-English explanation of your results and what they mean for your vehicle.
What Manufacturers Say About Tire Age
| Tire Age | Source | Statement |
|---|---|---|
| Under 6 years | No age limit reached | Bridgestone: if a tire is older than 6 years and shows aging, ask a tire expert. |
| 6–9 years | Vehicle maker guidance | Ford (2025 F-150), Mazda (CX-5, CX-9, CX-30, Mazda3, MX-5), GMC (2025 Sierra) and Tesla (Model 3, Model Y): replace at about 6 years. Toyota and Lexus: a tire over 6 years old must be checked by a qualified technician. Audi: use tires over six years old only when absolutely necessary. |
| 10+ years | Tire maker guidance | Michelin: replace tires in service 10 years or more from manufacture, including spares, even if they appear serviceable. Bridgestone: remove its tires from service after ten years regardless of tread depth. |
Statements are from NHTSA, Bridgestone and Michelin web pages and from the owner's manuals named (2023 to 2025 editions). Other makers may say something different; check your own manual and have a qualified professional inspect the tires.
How to Use This Calculator
- Find the DOT Tire Identification Number (TIN) on your tire sidewall. It starts with "DOT" and ends with the date code.
- Type or paste the full DOT code (for example DOT 4B2K 1923) or just the last 4 digits (1923). The calculator reads the date code from the end of what you enter.
- If the code ends in only 3 digits, the tire was manufactured before 2000. Bridgestone says a tire with a 3-digit date code should be replaced due to age.
- Read the manufacture week and the date that week began, the tire age in years and months, and the manufacturer statements shown for that age.
How to Read a DOT Code
NHTSA's tire identification rule, 49 CFR 574.5, says a new tire carries a 13-symbol Tire Identification Number molded into one sidewall. The groups are:
| Part | Length | What it means | Example |
|---|---|---|---|
| DOT symbol | 3 letters | Certifies that the tire conforms to the applicable Federal Motor Vehicle Safety Standards. | DOT |
| Plant code | 3 symbols (2 on older tires) | Identifies the tire manufacturer or retreader. NHTSA assigns it. Two-symbol plant codes could be used until April 13, 2025. | 4B2 |
| Manufacturer's code | 6 symbols | Used by the manufacturer to describe the tire or to identify the brand name owner. Its meaning is kept in the manufacturer's records. | K3R7XD |
| Date code | 4 digits | Week and year of manufacture: two digits for the week, two for the year. | 1923 |
Date code examples
Week 01 is the first full calendar week of the year, running Sunday through Saturday. The weeks below are calculated with that rule.
| Date code | Week | Year | Week begins (Sunday) |
|---|---|---|---|
| 0126 | 1 | 2026 | Jan 4, 2026 |
| 0725 | 7 | 2025 | Feb 16, 2025 |
| 1725 | 17 | 2025 | Apr 27, 2025 |
| 2326 | 23 | 2026 | Jun 7, 2026 |
| 2726 | 27 | 2026 | Jul 5, 2026 |
| 3026 | 30 | 2026 | Jul 26, 2026 |
| 1923 | 19 | 2023 | May 7, 2023 |
| 4221 | 42 | 2021 | Oct 17, 2021 |
| 4620 | 46 | 2020 | Nov 15, 2020 |
| 4720 | 47 | 2020 | Nov 22, 2020 |
Important: 3‑Digit DOT Codes = Pre‑2000 Tires
DOT Code & Tire Age Formula
About Tire Age, DOT Codes & Safety
Why Tire Age Matters More Than You Think
NHTSA explains that tire aging occurs when the rubber and other components in a tire change over time due to service, storage and environmental conditions. You cannot detect aging simply by looking at a tire, and exposure to sunlight and warmer climates, infrequent use, poor storage and poor maintenance all contribute. NHTSA says aging is a particular concern for recreational vehicles, 15-passenger vans, collector cars and other vehicles that are not driven regularly.
How Manufacturers and Safety Agencies View Tire Age
NHTSA says some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear. The owner's manuals we read say about 6 years (Ford, Mazda, GMC, Tesla), or that a tire over 6 years old must be checked by a qualified technician (Toyota, Lexus), and Michelin and Bridgestone give 10 years. These statements apply to spare tires as well: Ford, Michelin and Audi mention spares specifically; the spare tire size and compatibility chart lists the spares in the manuals we read.
Using This Tool as Part of a Safety Check
This calculator makes it easy to decode your DOT date code and see a clear estimate of your tire’s age, but it is only one part of a complete tire safety check. You should also monitor tread depth (NHTSA says tires are not safe and should be replaced when the tread is worn down to 2/32 of an inch), watch for uneven wear, inspect for cracks, bulges, or cuts, and maintain proper inflation pressure. The tread depth calculator turns a 32nds reading into remaining tread, and the prorated tire value estimate is useful if a tire is being sold or claimed on.
Reading the Rest of the Sidewall
The DOT code only gives the plant and the date. The size marking on the same sidewall, such as 225/45R17, is a separate code. The tire size decoder and converter breaks it into width, aspect ratio, rim diameter and overall diameter.
Frequently Asked Questions
Disclaimer
This tool decodes DOT codes and estimates tire age for informational and educational purposes only. Tire safety depends on age, storage, usage, inflation, load, damage, and many other factors that cannot be fully assessed by software. Always have tires inspected by a qualified professional and follow the most conservative guidance from your vehicle and tire manufacturers when deciding whether to keep or replace tires.