Maintenance procedure · Written to ASD-STE100 Issue 9 · Formatted to ANSI Z535

Tire Sidewall Markings and the DOT Date Code

Passenger car and light truck tires — find the tire identification number and read the age of the tire
ApplicabilityPassenger car and light truck tires sold in the United States
Task time9 min editorial estimate, not a measurement
PersonnelOne
Revisionv1 · 2026-07-29
BEFORE YOU BEGIN

Before you begin. This procedure is general reference information, not professional advice. Equipment varies by manufacturer, model, and year. Always follow the documentation supplied with your equipment — where it differs from this page, follow the manufacturer. Verify that you have the tools, the working conditions, and the ability to do this task safely. If anything is unclear, if the equipment is damaged, or if the task exceeds your experience, stop and use a qualified professional. You are responsible for your own safety and for the outcome. This site accepts no liability for any loss, damage, or injury arising from the use of this information.

Specifications marked unverified could not be traced to a manufacturer source. Do not rely on them — obtain the value from your equipment documentation.

Summary

Every tire carries its own date of manufacture, its size and its limits, moulded into the sidewall. The code that gives the age is the DOT Tire Identification Number, and the last four digits are the week and the year the tire was made. Federal regulation sets that format, so it reads the same way on every tire sold in the United States. This page shows you where to look and how to read what you find.

It does not tell you when to replace a tire, and it does not print a pressure. NHTSA says the correct inflation pressure is the one the vehicle manufacturer lists on the placard, not the maximum number moulded into the sidewall. Replacement age is a manufacturer question too, and vehicle makers and tire makers do not give the same answer. Both are marked here as consult-the-manufacturer on purpose.

Necessary equipment

ItemNote
Flashlight optionalThe light near a tire is often low.
ClothUse a cloth to remove dirt from the sidewall.
Pen and paperRecord the information for each tire.

Specifications

Maximum load rating
Unverified — do not rely on this value
READ THE VALUE FROM THE SIDEWALL. CONSULT THE VEHICLE PLACARD AND THE VEHICLE DOCUMENTATION BEFORE YOU LOAD THE VEHICLE.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Tire replacement age
Unverified — do not rely on this value
CONSULT THE VEHICLE MANUFACTURER AND THE TIRE MANUFACTURER

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Prepare the vehicle

Estimated under a minute

WARNING

STOP THE VEHICLE AWAY FROM TRAFFIC BEFORE YOU START.
Traffic can kill you.

  1. Stop the vehicle on a level surface away from traffic.
    <1mReport a problem with step 1, Prepare the vehicle
  2. Set the parking brake.
    <1mReport a problem with step 2, Prepare the vehicle
  3. If the light is low, use a flashlight.
    <1mReport a problem with step 3, Prepare the vehicle

Find the tire identification number

Estimated 2 min

CAUTION

IF DIRT HIDES THE MARKINGS, CLEAN THE SIDEWALL WITH A CLOTH.
Do not use a sharp tool. A cut in the sidewall can cause damage to the tire.

  1. Look at the sidewall of the tire.
    <1mReport a problem with step 1, Find the tire identification number
  2. Find the letters DOT on the sidewall.
    • The letters DOT are a certification mark from the United States Department of Transportation.
    • A new tire has 13 symbols after the letters DOT.
    • A retreaded tire has 7 symbols after the letters DOT.
    <1mReport a problem with step 2, Find the tire identification number
  3. If you do not find the letters DOT, look on the other side of the tire.
    • The regulation asks for the letters DOT on one sidewall only.
    <1mReport a problem with step 3, Find the tire identification number
  4. Find the group of four numbers at the end of the tire identification number.
    • The regulation calls this group the date code.
    <1mReport a problem with step 4, Find the tire identification number

Read the date code

Estimated 2 min

NOTEThe date code is the last group of the tire identification number.
  1. Read the first two numbers of the date code.
    <1mReport a problem with step 1, Read the date code
  2. The first two numbers give the week of manufacture.
    • A calendar week starts on a Sunday and ends on a Saturday.
    <1mReport a problem with step 2, Read the date code
  3. Read the last two numbers of the date code.
    <1mReport a problem with step 3, Read the date code
  4. The last two numbers give the last two digits of the year of manufacture.
    • For example, the date code 0109 is week 01 of 2009.
    <1mReport a problem with step 4, Read the date code
  5. Do the same steps for each tire on the vehicle.
    <1mReport a problem with step 5, Read the date code

Read the other markings

Estimated 2 min

NOTEThe vehicle placard gives the correct pressure for this vehicle.
Recommended cold inflation pressure
Unverified — do not rely on this value
CONSULT THE VEHICLE PLACARD. THE PLACARD IS ON THE PILLAR OR ON THE EDGE OF THE DRIVER DOOR.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Maximum inflation pressure
Unverified — do not rely on this value
READ THE VALUE FROM THE SIDEWALL. CONSULT THE VEHICLE PLACARD FOR THE CORRECT PRESSURE.

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

Tire size
Unverified — do not rely on this value
READ THE SIZE FROM THE SIDEWALL OR FROM THE VEHICLE PLACARD

No tier-1 source was found for this value. Take it from the documentation supplied with your equipment.

  1. Find the tire size on the sidewall.
    <1mReport a problem with step 1, Read the other markings
  2. Find the maximum inflation pressure on the sidewall.
    <1mReport a problem with step 2, Read the other markings
WARNING

DO NOT USE THE PRESSURE ON THE SIDEWALL.
The sidewall shows the maximum pressure. The correct pressure is on the vehicle placard. A tire at the wrong pressure can fail and injure you.

  1. Do not use the maximum inflation pressure as the correct pressure.
    <1mReport a problem with step 3, Read the other markings
  2. Open the driver door.
    <1mReport a problem with step 4, Read the other markings
  3. Find the vehicle placard on the pillar or on the edge of the door.
    <1mReport a problem with step 5, Read the other markings
  4. Read the recommended cold inflation pressure from the vehicle placard.
    • The vehicle placard also gives the tire size for this vehicle.
    <1mReport a problem with step 6, Read the other markings

Record the information

Estimated 2 min

NOTICE

Do not use one date code for all the tires.
Tires on one vehicle can have different dates.

  1. Record the week and the year of manufacture for each tire.
    1mReport a problem with step 1, Record the information
  2. Record the tire size for each tire.
    <1mReport a problem with step 2, Record the information
  3. Keep the record in the vehicle.
    <1mReport a problem with step 3, Record the information

Terminology

This page uses one term for each item and holds it throughout, as ASD-STE100 requires. Equipment sellers and other guides use the names below for the same parts.

tire identification number
Also called: DOT number, DOT code, TIN, tire serial number, the four digit code on a tire
date code
Also called: born on date, tire age code, week and year code, last four digits
sidewall
Also called: side of the tire, tire wall, the writing on the tire
vehicle placard
Also called: tire and loading information label, door jamb sticker, door sticker, tire placard, B-pillar sticker
maximum inflation pressure
Also called: max psi, max pressure, the psi on the tire
recommended cold inflation pressure
Also called: correct tire pressure, recommended psi, door sticker pressure, proper tire pressure
retreaded tire
Also called: retread, recap, remould

When to use a professional

Stop if the sidewall has a cut. Stop if the sidewall has a bulge. Stop if the tire has a crack. Speak to a tire specialist.

A tire specialist must tell you when to replace a tire. This page does not give a replacement age. Vehicle manufacturers and tire manufacturers do not agree on an age. Read the documentation for your vehicle and your tires.

Common questions

How do I tell how old my tires are?

Look on the sidewall for the DOT Tire Identification Number and read the last four digits. The first two are the week of manufacture and the last two are the year. NHTSA gives the example 0308, which is a tire made in the third week of 2008. The number may be moulded on only one side of the tire, so look at both sides before you decide it is missing.

What does the 4 digit number on my tire mean?

It is the date code, the final group of the DOT Tire Identification Number. Federal regulation 49 CFR 574.5 requires four numerals: the week of the year, then the last two digits of the year. Week 01 is the first full calendar week of the year, and a calendar week runs from Sunday to Saturday.

What is the DOT number on a tire?

The letters DOT are a certification that the tire conforms to an applicable Federal Motor Vehicle Safety Standard. What follows is the Tire Identification Number: a plant code, then a manufacturer's code, then the date code. Under 49 CFR 574.5 a new tire carries 13 symbols and a retreaded tire carries seven.

Should I use the psi printed on my tire sidewall?

No. That number is the maximum permissible inflation pressure for the tire, not the right pressure for your vehicle. NHTSA is explicit that the correct pressure for your tire is what the vehicle manufacturer has listed, not what is listed on the tire itself. It is on the Tire and Loading Information placard, and 49 CFR 571.110 is what requires that placard to carry it.

How old is too old for a tire?

This page will not give you a number, because there is no single right one. NHTSA notes that some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old regardless of treadwear, which is a range and an attribution rather than a rule. Your vehicle documentation and your tire maker are the authorities for your own tires. Read the date code first, so you know what you are asking them about.

Where is the tire and loading information sticker?

On the driver's side B-pillar in most vehicles. Where there is no B-pillar, or a placard there would not be legible, 49 CFR 571.110 allows the rear edge of the driver's side door or a position next to the driver's seat. NHTSA describes it as the label on the driver's side door edge, which is where most people find it.

No related procedure is published yet. This section fills as the repository grows.

Sources

Every specification on this page is traced to one of these sources. Tier 1 is a manufacturer document, a published standard, or a government safety authority. See Standards for the full tiering rule.

  1. Tier 1Tire Safety Ratings and Awareness (TireWise)National Highway Traffic Safety Administration · accessed 2026-07-29 · re-verification due 2027-01-25 · automated link check returned 403 — verified by hand
  2. Tier 149 CFR 574.5 — Tire identification requirementsOffice of the Federal Register (eCFR) · accessed 2026-07-29 · re-verification due 2027-01-25
  3. Tier 149 CFR 571.110 — FMVSS No. 110, Tire selection and rimsOffice of the Federal Register (eCFR) · accessed 2026-07-29 · re-verification due 2027-01-25

Revision history

Current version 1 · updated 2026-07-29 · next review due 2027-07-29

  1. v1 · 2026-07-29First draft. Built from 49 CFR 574.5, 49 CFR 571.110 and NHTSA TireWise. Every equipment-specific value publishes as consult-the-manufacturer.

Corrections to this page are listed in the public corrections log. Reports that are credible and not yet verified are listed in the public errata register, and an open one renders above the step it concerns.

Comments and corrections

Found an error? A correction with a manufacturer source is applied and logged publicly. You can also write to corrections@fixchecklist.com.

Every step above carries its own report control, which tags the report with that step so a correction reaches the right place. For anything about the procedure as a whole — the order of the sections, a step that is missing, something that did not match your equipment — use this: report something about this whole procedure.

The comment system is not connected yet. Comments are stored in GitHub Discussions through Giscus, outside this site, so that a redeploy cannot destroy them.