How to Check the Date on a Tire (And What the Numbers Actually Mean)
Every tire manufactured for sale in the United States carries a date code stamped directly into the sidewall. It's not hidden — but it's not obvious either. Once you know what to look for, reading it takes about five seconds.
Where to Find the Tire Date Code
The date is embedded within a longer alphanumeric string called the DOT code (Department of Transportation). This code is molded into the sidewall of the tire, typically on the inner sidewall — the side facing toward the vehicle — though it often appears on the outer sidewall as well.
The DOT code starts with the letters "DOT" followed by a series of characters. The last four digits of that string are the ones you want: they represent the tire's manufacture date.
Example: DOT U2LL LMLR 1318
The last four digits — 1318 — break down as:
- 13 = the 13th week of the year
- 18 = the year 2018
So that tire was made during the 13th week of 2018 (late March or early April 2018).
That's the entire method. Find the DOT code, read the last four digits, split them into two pairs.
How to Read the Week and Year
| Digit Position | What It Tells You | Example |
|---|---|---|
| First two digits | Week of manufacture (01–52) | 13 = 13th week |
| Last two digits | Year of manufacture | 18 = 2018 |
Weeks run from 01 (first full week of January) through 52 or sometimes 53. If a code ends in 0423, that tire was made in the fourth week of 2023 — late January 2023.
One thing to watch for: Tires made before 2000 used a three-digit code instead of four. If you're looking at an older spare or a vintage vehicle's tires, you might see something like 429 — meaning the 42nd week of 1999. The switch to four digits happened at the turn of the millennium. Any tire with a three-digit date code is well past its service life.
Why the Manufacture Date Matters 🕐
Rubber ages. Even a tire that has never been driven on — sitting in a garage or mounted as a spare — degrades over time. The oils and chemicals in rubber compound gradually evaporate and oxidize, causing the material to harden and crack.
This matters because:
- Unused tires can still be aged tires. Low tread depth is the obvious sign of a worn tire. Age-related degradation is less visible but still affects safety.
- Tires on infrequently used vehicles age faster in some conditions. Heat, UV exposure, and ozone accelerate the process.
- Spare tires are frequently overlooked. The spare mounted under a truck bed or in a wheel well may have been sitting there for a decade without anyone checking it.
How Old Is Too Old? The Variables That Matter
There's no universal legal cutoff for tire age in the United States, though that's worth understanding in some detail.
Tire manufacturers generally recommend replacing tires that are six to ten years old, regardless of appearance or tread depth. Most major manufacturers use a ten-year maximum from the date of manufacture as an outer limit.
Vehicle manufacturers sometimes set their own guidance — often more conservative. Some specify replacement at six years, particularly for spare tires and vehicles stored or driven infrequently.
What varies:
- Vehicle type — Tires on trailers, RVs, and vehicles used seasonally tend to age faster because they sit more than they roll
- Climate — Hot, sunny climates (think Arizona or Florida) accelerate UV and heat degradation compared to cooler, shaded storage
- Storage conditions — Tires kept in temperature-controlled, dark environments hold up better than those exposed to the elements
- Inflation history — Chronically underinflated tires wear and stress differently, even when not visibly cracked
None of these factors appear in the DOT code. The manufacture date tells you when a tire was made — not how it was stored, where it lived, or how hard it worked. 🔍
Checking Multiple Tires on the Same Vehicle
The four tires on a vehicle don't have to match in age. A vehicle may have had one or two tires replaced at different times, leaving a mix of manufacture dates. This is normal — but it's useful to know what you have.
When buying a used vehicle, checking the DOT date on all four tires (plus the spare) gives you a clearer picture of what you're inheriting. Two tires from 2021 and two from 2014 on the same axle is a detail worth knowing, even if both sets still show tread.
What the Date Code Doesn't Tell You
The DOT code confirms manufacture date. It doesn't confirm:
- Whether a tire has been repaired or plugged
- Whether it's been run while flat (which can cause internal structural damage invisible from outside)
- Whether it's the right load rating or speed rating for the vehicle it's on
- Its full service history
Those variables require physical inspection — checking for sidewall cracking, bulging, unusual wear patterns, and matching the tire specs to the vehicle's requirements.
The date code is one data point. It's a reliable one, and it's worth knowing. But what that date means for a specific tire on a specific vehicle depends on factors the sidewall simply can't tell you.
