To learn how to read DOT numbers on tires, find the code beginning with “DOT” on the tire sidewall and identify its final four digits. The first two digits show the manufacturing week, while the last two show the year, so a code ending in 3524 means the tire was made during week 35 of 2024.
Key Facts at a Glance
- A DOT Tire Identification Number begins with the letters DOT.
- The final four digits on a modern tire use the WWYY format.
- A date code of 1422 means week 14 of 2022.
- The complete DOT number may appear on only one sidewall.
- Tire age must be considered with tread depth, cracking, damage, pressure history, and performance.
- A three-digit date code normally identifies a tire manufactured before 2000.
Before You Start
Reading a DOT number takes about two to five minutes per tire. No mechanical experience is required, but the code may be difficult to see when it faces the suspension or when road grime fills the molded characters.
| Requirement | Typical need | Purpose |
| Inspection time | 2-5 minutes per tire | Locate, clean, record, and decode the TIN |
| Difficulty | Beginner | No tire removal is normally needed |
| Cost | $0 | A flashlight and phone are usually enough |
| Flashlight | 1 | Illuminates the inward-facing sidewall |
| Cleaning cloth | 1 | Removes dirt without damaging the rubber |
| Phone camera | 1 | Captures and enlarges difficult characters |
| Wheel chock | 1-2 | Helps prevent vehicle movement while inspecting |
| Tire professional | As needed | Checks unreadable codes, cracking, bulges, or internal concerns |
Park on level ground, switch off the engine, set the parking brake, and keep your body away from moving traffic. Do not crawl beneath a vehicle supported only by a jack.
Step 1: Find the Marking That Begins With DOT
Look along the tire sidewall for a molded sequence beginning with the capital letters DOT. DOT is normally followed by groups of letters and numbers, such as:
DOT 1M6 ABCD 1422
The DOT symbol indicates that the manufacturer certifies the tire as conforming to applicable federal motor-vehicle safety standards. It is not the tire’s model name, inflation recommendation, treadwear grade, or retail size. NHTSA describes the Tire Identification Number as the sidewall code used to determine the tire’s manufacturing date and support tire identification.
You will know you found the correct marking when the sequence starts with DOT and, on the complete-code side, ends with four numbers.
DOT Number Versus Other Tire Markings
| Sidewall marking | Example | What it identifies |
| DOT Tire Identification Number | DOT 1M6 ABCD 1422 | Plant, manufacturer-controlled data, and manufacture date |
| Tire size | P215/60R16 | Width, aspect ratio, construction, and rim diameter |
| Service description | 95H | Load index and speed rating |
| Maximum pressure | MAX PRESS 51 PSI | Tire’s maximum marked pressure, not normal vehicle pressure |
| Vehicle pressure recommendation | 35 PSI on door placard | Automaker’s recommended cold inflation pressure |
| UTQG grade | 500 A A | Treadwear, traction, and temperature classifications |
| Winter marking | 3PMSF symbol | Tested snow-traction qualification |
| Construction wording | RADIAL TUBELESS | Casing construction and tube requirement |
Do not use the pressure molded into the tire sidewall as the vehicle’s normal inflation setting. Michelin directs drivers to the vehicle placard or owner’s manual for the manufacturer-specified operating pressure.
Step 2: Locate the Complete DOT Number
Check both sidewalls because the complete Tire Identification Number may not be equally visible on each side. NHTSA specifically advises drivers to look on both sides because the full TIN may not appear on both sidewalls.
One side may show a partial sequence without the four-digit manufacturing date. When that happens, the full sequence is usually molded on the opposite side, which may face the vehicle’s suspension.
Use these methods before considering tire removal:
- Roll the vehicle forward or backward several inches to reposition the code.
- Turn the steering wheel to expose the inner sidewall of a front tire.
- Shine a flashlight across the sidewall at a shallow angle.
- Use a phone camera or mirror to inspect the inward-facing surface.
- Clean the area with a damp cloth if dirt hides the characters.
Do not place your head or arm underneath a vehicle that is raised improperly. A tire shop can inspect an inaccessible date code safely on a lift.
Success checkpoint: You have found a DOT sequence ending in a separate block of four digits.
Common mistake: Treating the shorter code on the visible side as the complete number. A code ending in letters or in a non-date grouping may be a partial TIN.
Step 3: Separate the DOT Number Into Sections
A modern DOT number contains identification groups rather than one continuous consumer-readable sentence. The exact arrangement can vary with the regulation period and tire, but the sequence generally identifies the manufacturing plant, manufacturer-controlled tire information, and production date.
| Code section | Typical appearance | Consumer meaning |
| DOT prefix | DOT | Manufacturer’s federal safety-standard certification |
| Plant code | 2 or 3 characters | Factory assigned through the federal identification system |
| Manufacturer-controlled section | Letters and numbers | Tire characteristics, size-related data, construction, or internal traceability |
| Date code | Final 4 digits | Week and year of manufacture in WWYY format |
The middle characters are mainly used for product identification, traceability, and recalls. They should not be assumed to match the familiar size format printed elsewhere on the sidewall.
For example:
DOT 1M6 ABCD 1422
- DOT identifies the federal certification marking.
- 1M6 is the plant-identification section.
- ABCD represents manufacturer-controlled identification characters.
- 1422 means production occurred in the 14th week of 2022.
Federal rules use the TIN to identify tires for safety and recall purposes. Historical NHTSA interpretations describe the sequence as containing a manufacturer or plant identifier, tire information, an optional type code, and a manufacturing-date group.
Success checkpoint: You can distinguish the final date block from all preceding letters and numbers.
Common mistake: Assuming every four-character block is a date. The manufacturing date is the final numerical group on the complete TIN.
Step 4: Decode the Final Four Digits
Read the last four digits as WWYY, meaning week and year. The first pair identifies the production week, normally from 01 through 52 or sometimes 53. The second pair identifies the final two digits of the year.
Modern DOT Date Code Examples
| Date code | Manufacturing week | Manufacturing year | Approximate calendar period |
| 0126 | Week 1 | 2026 | Early January 2026 |
| 1422 | Week 14 | 2022 | Early April 2022 |
| 2524 | Week 25 | 2024 | Mid-June 2024 |
| 3524 | Week 35 | 2024 | Late August 2024 |
| 4720 | Week 47 | 2020 | Mid-to-late November 2020 |
| 5320 | Week 53 | 2020 | Final week crossing into early 2021 |
Do not read 1022 as October 2022. It means the tenth manufacturing week of 2022.
Likewise, 3524 does not mean March 5, 2024, May 3, 2024, or the 35th day of 2024. Tire date codes do not use month-day-year formatting.
Michelin provides the same interpretation: the first two digits represent the week and the last two represent the year. Its example 4714 means the 47th week of 2014.
Success checkpoint: Both halves produce a plausible result, including a week from 01 through 53 and a reasonable manufacturing year.
Common mistake: Reading a group such as 4B21 as a date. A modern date block contains four numbers, not letters.
Step 5: Validate the Code Before Calculating Tire Age
A valid-looking code still needs a basic logic check. The week portion should normally fall between 01 and 52, with 53 possible in applicable years. A reading of 00, 67, or 99 is not a valid production week and usually means the wrong block was selected or a character was misread.
Use this validation checklist:
- Confirm that the sequence begins with DOT.
- Confirm that you are viewing the complete-code side.
- Use the final four numerical characters.
- Check that the first two digits form a plausible week.
- Compare the year with the vehicle, purchase, and tire service history.
- Photograph the code and enlarge it when 3, 5, 6, 8, and 9 appear similar.
- Check all four road tires instead of assuming they match.
- Inspect the spare tire separately.
A tire on a 2018 vehicle could carry a 2017 date because components are produced before final vehicle assembly. A tire marked 2025 on a vehicle sold in 2024, however, signals that the code or vehicle timeline has been misunderstood.
What Does Each Part of a DOT Number Mean?
The final four digits provide the most useful information for an ordinary owner, but the complete DOT number has a wider regulatory purpose. It supports manufacturer identification, product traceability, registration, and recall administration.
The DOT Prefix
The letters DOT are a certification marking. They do not mean the Department of Transportation individually inspected that specific tire before sale.
The Plant Code
The first identification group after DOT identifies the manufacturing plant. Plant codes should be checked through a current, authoritative database because assignments and formatting systems can change.
The plant code can answer where the tire was manufactured, but it does not independently show whether the tire is safe, genuine, correctly stored, or suitable for a particular vehicle.
The Manufacturer-Controlled Characters
The middle characters identify information selected under the applicable TIN structure, such as tire characteristics or internal production details. Consumers usually cannot decode every character from general sidewall knowledge because some information is manufacturer-specific.
The Date Code
The final four numbers identify the production week and year. This is the section used to calculate tire age and compare the tire with age-related inspection or replacement guidance.
How Old Is a Tire Based on Its DOT Number?
Calculate tire age from the manufacturing week, not from the purchase or installation date. A tire marked 1422 was manufactured in approximately April 2022, even if a retailer sold and installed it in 2023.
| DOT ending | Approximate production date | Age in August 2026 | Practical interpretation |
| 0526 | Early February 2026 | About 6 months | Recently manufactured |
| 3524 | Late August 2024 | About 2 years | Age alone is not unusual |
| 1422 | Early April 2022 | About 4 years, 4 months | Begin considering age within routine inspections |
| 3020 | Late July 2020 | About 6 years | Review manufacturer guidance and condition carefully |
| 1517 | Mid-April 2017 | About 9 years, 4 months | Near or beyond many maximum-life recommendations |
| 4014 | Early October 2014 | About 11 years, 10 months | Beyond the 10-year maximum used by several manufacturers |
The date is only one part of the decision. Michelin states that age alone does not determine serviceability and that tread wear and overall condition also matter. Michelin recommends professional annual inspections after five years and replacement by ten years from manufacture.
NHTSA notes that some vehicle and tire manufacturers recommend replacement at six to ten years, regardless of remaining tread. The agency advises owners to follow the recommendations applicable to their vehicle and tire.
Is an Older Tire Automatically Unsafe?
An older tire is not judged by the date code alone, but age increases the need for careful inspection and manufacturer-specific decision-making. Temperature, inflation, load, speed, impact damage, storage, sunlight, maintenance, and operating conditions all affect how tire materials change over time.
Replace or professionally inspect a tire promptly when you find:
- A sidewall bulge or bubble
- Deep cracking or exposed cords
- A cut, puncture, or impact injury
- Persistent vibration or pressure loss
- Irregular or severe tread wear
- Tread at the legal or manufacturer replacement threshold
- A recall affecting the tire
- Age at or beyond the tire or vehicle manufacturer’s maximum recommendation
A tire with deep tread can still be unsuitable because tread depth does not reveal every age-related or internal condition. Conversely, a relatively new tire may require immediate replacement after impact damage, underinflated operation, overloading, or structural injury.
NHTSA summarizes the principle directly: “As tires age, they are more prone to failure.”
What Do Three-Digit DOT Date Codes Mean?
A three-digit date code normally indicates a tire manufactured before 2000. The first two numbers show the week, while the final number shows only the last digit of the year, creating decade ambiguity.
For example, 439 identifies week 43 of a year ending in 9. Without additional evidence, the digits alone could refer to 1979, 1989, or 1999.
Some tires produced during the 1990s used a small triangle after the three-digit date group to distinguish that decade. NHTSA records show that European manufacturers proposed the triangle to identify tires produced from 1990 through 1999.
| Older code | Basic meaning | Decade issue | Current action |
| 346 | Week 34, year ending in 6 | Could indicate 1986 or 1996 | Treat as far beyond normal road service life |
| 439 | Week 43, year ending in 9 | Could indicate 1979, 1989, or 1999 | Do not rely on remaining tread |
| 439 plus triangle | Week 43 of 1999 | Triangle was used for the 1990s | Replace rather than continue normal road use |
| 101 | Week 10, year ending in 1 | Decade cannot be confirmed from digits alone | Professional evaluation is not a substitute for age limits |
Any genuine three-digit code represents a tire that is more than 26 years old in 2026. Such a tire should not be treated as serviceable merely because it holds air or has visible tread.
Why Can’t I Find the Tire Date Code?
The most common reason is that you are looking at the partial-code sidewall. The full date-bearing TIN may face inward, especially when the tire’s intended mounting orientation places the complete number toward the suspension.
Other causes include:
| Problem | What you may see | Practical solution |
| Partial TIN | DOT sequence ends without four numbers | Inspect the opposite sidewall |
| Dirt in molding | Characters appear shallow or incomplete | Wipe with water and a soft cloth |
| Poor lighting | 3, 5, 6, 8, and 9 look alike | Use side lighting and a phone photo |
| Wheel position | Code sits behind the fender or near the ground | Roll vehicle slightly or turn steering |
| Cosmetic dressing | Gloss creates glare | Wipe the local area before photographing |
| Sidewall damage | Code is scuffed or unreadable | Ask a tire professional to inspect it |
| Missing DOT prefix | You found size or model markings instead | Continue around the full circumference |
| Code ends in letters | Likely not the date-bearing ending | Find the complete sequence on the other side |
Do not guess an unreadable date. A tire dealer may be able to inspect the opposite side safely, but a missing or destroyed identification section can also complicate age verification and recall checks.
Common Mistakes and How to Fix Them
Mistake 1: Reading the Tire Size as the DOT Number
A marking such as P225/65R17 102H identifies size and service characteristics, not manufacturing date.
Fix: Find a separate sequence beginning with DOT and ending in four digits.
Mistake 2: Treating Any Four Digits as a Date
Plant or manufacturer codes may contain numbers that resemble dates.
Fix: Use only the final four numerical characters of the complete DOT sequence.
Mistake 3: Converting the First Pair Into a Month
A code ending in 1123 does not mean November 2023. It means week 11 of 2023.
Fix: Read the first pair as a week number.
Mistake 4: Inspecting Only One Tire
Replacement tires, axle pairs, and spare tires may have different manufacturing dates.
Fix: Record the DOT ending from every tire separately.
Mistake 5: Assuming Installation Date Equals Manufacture Date
A tire may remain in distribution or storage before installation.
Fix: Base age calculations on the molded DOT date, then consider storage and service history.
Mistake 6: Using Age as the Only Safety Test
A date code cannot reveal every puncture, impact, underinflation event, repair, or internal injury.
Fix: Combine age with a physical inspection, tread measurement, pressure history, performance symptoms, and manufacturer guidance.
How to Check DOT Numbers When Buying Tires
Check the date code before buying used tires, a used vehicle, an RV, a trailer, or tires represented as new inventory. Manufacturing age can affect how much usable time remains under a manufacturer’s maximum-age guidance.
New Tires
A recently manufactured date is generally preferable, but an older unused tire is not automatically defective. Storage conditions, manufacturer policy, warranty terms, and expected annual mileage matter.
Ask the seller:
- When did the shop receive the tire?
- Was it stored indoors away from sunlight, heat, ozone sources, and moisture?
- When does the warranty period begin?
- Can the shop provide a newer production batch?
- Do all tires in the set have reasonably similar dates?
Used Tires
Used tires require more than a date-code check. Their inflation, load, repair, impact, storage, and internal-damage histories may be unknown.
A low price does not offset uncertainty about structural condition. Have a qualified tire professional inspect used tires internally and externally before installation.
Used Vehicles
Check all four road tires and the spare. A seller may accurately describe the tread as deep while overlooking advanced age, cracking, mismatched dates, or a very old spare.
RVs and Trailers
Low annual mileage does not stop material aging. Long periods of parking can expose tires to sunlight, heat, moisture, localized loading, and underinflation.
Motorcycles
Motorcycle tires use the same four-digit week-year principle. Michelin’s motorcycle guidance states that the first two digits identify the week and the final two identify the year.
Expert Rules for Interpreting Tire Dates
Rule 1: Check the spare before you need it. A full-size spare may look unused because it has never contacted the road, yet its manufacturing date may be older than the vehicle’s current tires. NHTSA warns that spare tires age even when they are seldom used.
Rule 2: Treat mismatched dates as a service-history clue. Different dates are not automatically unsafe, but they may indicate piecemeal replacement, collision repair, puncture replacement, rotation problems, or inconsistent maintenance.
Rule 3: A newer date cannot cancel visible damage. A two-year-old tire with a bulge, exposed cord, deep cut, or severe pressure loss requires action sooner than an older tire that merely looks cosmetically clean.
Rule 4: The DOT code identifies manufacturing time, not remaining life. Remaining usability depends on the tire manufacturer’s guidance and the tire’s physical and operational history.
Limitations of a DOT Number
A DOT number cannot certify that a tire was stored correctly, maintained at the proper pressure, repaired according to accepted procedures, or protected from overload and impact damage. It also cannot reveal every internal separation or structural injury.
The plant code may identify a facility, but it does not prove that an online listing is genuine. Counterfeit concerns require examination of the seller, molded markings, product specifications, purchase records, and manufacturer verification.
Most importantly, decoding a date is not a substitute for professional inspection. The DOT number provides traceability and age information. It does not provide a complete safety diagnosis.
FAQ
Can a DOT date code contain letters?
The manufacturing-date section on a modern tire contains four numbers. Letters can appear elsewhere in the DOT Tire Identification Number, including the plant and manufacturer-controlled sections. When the apparent final block contains a letter, you may be viewing an earlier code group or the partial TIN on the opposite sidewall.
Does DOT 3524 mean the tire expires in 2035?
No. A DOT code ending in 3524 means the tire was manufactured during the 35th week of 2024. It does not state an expiration date. Replacement timing depends on manufacturer guidance, physical condition, tread, damage, operating history, maintenance, storage, and vehicle requirements.
Is a five-year-old unused tire still new?
It may be legally sold as unused inventory, but its rubber is still five years old from the manufacturing date. Ask about storage conditions, warranty coverage, manufacturer guidance, and available newer stock. A tire’s service history may begin at installation, but its calendar age begins when it was manufactured.
Why do the four tires have different DOT dates?
Tires are often produced in different weeks or replaced at different times. Small differences do not automatically indicate a problem. Large differences can reveal piecemeal replacement or an older tire retained after the others were changed, so compare tread, condition, specifications, and service records.
Can I look up a tire recall using the DOT number?
Yes. The TIN contains identification information used in tire recall and registration systems. Record the complete code accurately, not only the date ending. A manufacturer, dealer, or official recall database may need the plant and product-identification characters to determine whether a specific tire is affected.
Does a DOT number show the tire’s recommended pressure?
No. The DOT number identifies the tire for regulatory and traceability purposes. Find the vehicle manufacturer’s recommended cold inflation pressure on the driver-door placard, fuel-door label, glove compartment label, or owner’s manual. The maximum pressure molded on the tire is not automatically the correct operating pressure.
The Bottom Line
To understand how to read DOT numbers on tires, locate the complete sidewall sequence beginning with DOT and decode its final four digits as manufacturing week and year. A code ending in 1422 means week 14 of 2022.
Check both sidewalls, validate that the week falls between 01 and 53, and inspect every road tire plus the spare. Use the date as one safety factor alongside tread depth, cracking, bulges, pressure history, damage, performance symptoms, recalls, and the replacement guidance issued by the tire and vehicle manufacturers.
