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Tire age & DOT date code guide

# Tire age & DOT date code guide

## What is the tire DOT date code?

The last four digits of a complete DOT Tire Identification Number show the manufacturing week and year. Age alone cannot confirm that a tire is serviceable: inspect pressure, wear, damage and performance, and follow the tire and vehicle maker. NHTSA says some makers recommend replacement at 6–10 years; Michelin recommends annual professional inspection after five years and replacement by ten; Continental advises removing tires over ten years, including spares.

DOT date code

Enter the 4-digit DOT date code from your tire sidewall — the week and year it was made.

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## Where to find the DOT code

The DOT code is moulded into the sidewall of the tire, usually on the inner sidewall (facing the vehicle). Look for the letters DOT followed by a string of letters and numbers. The last four digits are the date code. Example:

DOT U2LL LMLR 2318 → manufactured in week 23 of 2018.

## DOT date code examples

| Last 4 digits | Week | Year | Meaning |
| --- | --- | --- | --- |
| **2318** | 23 | 2018 | Week 23 of 2018 (approx. June 2018) |
| **0421** | 04 | 2021 | Week 4 of 2021 (approx. January 2021) |
| **5223** | 52 | 2023 | Week 52 of 2023 (approx. December 2023) |

## Tire age replacement guide

| Age | Condition | Recommended action |
| --- | --- | --- |
| **< 5 years** | No age-only verdict | Continue pressure, wear and damage checks; age alone does not confirm serviceability. |
| **5–6 years** | Increase scrutiny | Michelin recommends annual professional inspection after five years of service. |
| **6–10 years** | Maker guidance varies | Follow the exact tire and vehicle-maker limit; damage, wear or performance changes can require earlier replacement. |
| **> 10 years** | Precautionary replacement benchmark | Michelin recommends replacement by ten years; Continental advises removing tires over ten years, including spares. |

## What causes old tires to fail?

- **Oxidation** — rubber reacts with oxygen and UV over time, causing the polymer chains to harden and crack.
- **Ozone cracking** — visible as fine surface cracks on the sidewall or between tread blocks. Accelerated by heat, UV exposure, and ozone.
- **Belt separation** — the steel or fabric carcass can delaminate from the tread in aged tires, causing sudden blowout.

## Pre-2000 tires: 3-digit date codes

Tires made before 2000 used a three-digit code: first two digits = week, third digit = year of the decade (e.g., 234 can mean week 23 of 1994 or 1984). Any such tire is far beyond the manufacturer age benchmarks cited here; remove it from road service and have the wheel and spare plan checked professionally.

## Tire-age sources reviewed

The DOT decoding and age boundaries above were checked against current government and tire-maker guidance. These are not a universal legal limit.

- [NHTSA TireWise: aging, damage, performance and the DOT TIN date field](https://www.nhtsa.gov/vehicle-safety/tires)
- [NHTSA electronic TIN study: old and standardized identification-number formats](https://www.nhtsa.gov/sites/nhtsa.gov/files/2023-05/Electronic-Tire-Identification-Study-tag.pdf)
- [Michelin: annual professional inspection after five years and replacement by ten](https://www.michelinman.com/auto/auto-tips-and-advice/tire-buying-guide/when-do-i-need-new-tires)
- [Continental: age factors and removal from service over ten years, including spares](https://www.continental-tires.com/ca/en/tire-knowledge/replacing-tires/)

Checked: 2026-08-21

## More tools

- [How to read a tire size](https://tirefitlab.com/learn/how-to-read-tire-size/)
- [Tire type guide](https://tirefitlab.com/learn/tire-types/)
- [Tire size calculator](https://tirefitlab.com/tire-size-calculator/)
- [Tire & wheel reference guides](https://tirefitlab.com/learn/)

[Last reviewed: 2026-08-21](https://tirefitlab.com/methodology/)

Seasonal check

## Planning a long summer drive?

Use the budget and running-cost tools before a trip, especially if the current tires are worn or the replacement size changes diameter.

[Estimate tire budget](https://tirefitlab.com/tire-budget-calculator/)

## More in this topic: Ownership and maintenance

Pressure, age, wear, cost and service decisions after the tires are fitted.

- [**Tire pressure guide** What PSI should your tires be? How to find the correct pressure, what the TPMS light means, effects of over- and under-inflation, and how temperature changes pressure.](https://tirefitlab.com/learn/tire-pressure/)
- [**Cold tire pressure guide** How cold tire pressure works: the 1 PSI per 10°F (0.1 bar per 8°C) temperature rule, when to check pressure (cold only), morning vs driven-tyre readings, altitude effects, and seasonal adjustment.](https://tirefitlab.com/learn/cold-tyre-pressure/)
- [**Tire pressure for heavy loads and towing** When and how to increase tire pressure for heavy loads: XL (Extra Load) tire pressure requirements, laden vs unladen recommended pressure, adjusting rear axle pressure when towing, front vs rear axle pressure differences, and what happens when you tow on under-inflated tires.](https://tirefitlab.com/learn/tyre-pressure-load/)
- [**Trailer and caravan tire pressure guide** Correct tire pressure for trailers, caravans, and horse boxes: why trailer tires are inflated much higher than car tires, how to find the right spec, load-dependent pressures, and the consequences of under-inflation on a towed vehicle.](https://tirefitlab.com/learn/trailer-tyre-pressure/)

### Useful tools

[Tire age calculator (DOT date code)](https://tirefitlab.com/tire-age-calculator/)