How to Check the Year of a Tire (and Why It Matters)

Every tire sold in the United States carries a code that tells you exactly when it was manufactured — down to the week. Most drivers never look at it. But knowing how to read that code is one of the simplest ways to catch a safety risk before it becomes a blowout.

What the DOT Code Is and Where to Find It

The DOT (Department of Transportation) code is a string of characters molded into the sidewall of every tire. It begins with the letters "DOT" and ends with a four-digit sequence called the manufacture date code — the part that tells you the tire's age.

Look for it on the inner or outer sidewall, near the rim. It's not always on the side facing out, so you may need to crouch down and look at the side facing the vehicle. The full string can be 8–13 characters long and may look something like this:

That last four-digit group — 2318 — is what you're after.

How to Read the Four-Digit Date Code 🔍

The four digits are split into two pairs:

• First two digits = the week of manufacture (01–52)
• Last two digits = the year of manufacture

So 2318 means the tire was made in the 23rd week of 2018.

That's the entire formula. No special tools, no apps, no guesswork.

A Note on Tires Made Before 2000

If you're looking at a vintage vehicle or an old spare that's been sitting around, you might find a three-digit date code instead of four. This format was used before the year 2000. A code like 318 meant the 31st week of the 8th year of that decade — but which decade was ambiguous. This is one reason those older tires are considered unreliable for determining age precisely.

For any tire manufactured after January 1, 2000, the four-digit format is standard.

Why Tire Age Matters Even When Tread Looks Fine

Rubber degrades over time regardless of how much a tire has been driven. Oxidation, UV exposure, heat cycles, and ozone all break down the rubber compounds from the inside out. A tire can have plenty of tread depth remaining and still be dangerously compromised structurally.

This is why tire age is treated separately from tread wear:

• Tread depth measures how much rubber is left above the wear bars
• Tire age measures how long that rubber has been deteriorating

A tire that sat in a garage for eight years before being installed has eight years of aging, even if it shows almost no tread wear. The same applies to the spare tire in your trunk — it ages at the same rate as your mounted tires, whether it's ever been used or not.

What Age Guidelines Generally Look Like

Tire manufacturers, vehicle manufacturers, and safety organizations each publish their own guidance on tire replacement timelines. These aren't uniform across the industry:

• Some tire manufacturers recommend replacing tires after six years regardless of condition
• Some vehicle manufacturers recommend replacement at six to ten years from the manufacture date
• The National Highway Traffic Safety Administration (NHTSA) has noted that tires degrade over time and recommends following manufacturer guidelines
• Many professional mechanics and safety advocates use ten years as an outer limit, even for tires that appear undamaged

The key variable is that these are general guidelines, not universal rules. A tire's actual condition depends on climate, storage conditions, load, inflation history, and driving environment. Tires in hot, sunny climates typically show accelerated aging compared to those kept in cool, dry conditions.

The Difference Between New and "New Old Stock" Tires 🗓️

When buying replacement tires — whether from a retailer, an online seller, or a private party — it's worth checking the date code before installation. New old stock refers to tires that were manufactured years ago but never used. They may look brand-new, but the manufacture date determines their age, not whether they've been mounted.

A tire made four years ago and sold today has four years of aging on it. Some shops will discount older inventory without disclosing the manufacture date. Checking the DOT code yourself is the only way to know what you're actually buying.

What Shapes Your Situation

Tire age guidelines look different depending on:

• Climate and region — high-heat or high-UV environments accelerate degradation
• How and where tires are stored — garage-kept vs. outdoor exposure
• Vehicle type and load — heavier vehicles place more stress on aging rubber
• Tire construction and compound — some formulations age more gracefully than others
• Whether the tire is a spare — spares are often ignored during routine inspections

Your vehicle's owner's manual may include specific tire age guidance from the manufacturer. The date code on your tires is where you start — what you do with that information depends on the tires themselves, the vehicle they're on, and the conditions they've lived in.