What Is DOT Number on Tires? | Decode Sidewall Codes

A DOT tire code is the sidewall ID that shows where a tire was made and when it was built.

When people ask what is DOT number on tires, they’re usually talking about the string of letters and numbers stamped after the letters DOT on the sidewall. That code is the tire’s ID tag. It helps trace the tire back to its plant, its build batch, and its production date.

The code can help you spot an older tire at the shop, match a set on a used car, and see whether a recall notice applies to your tire. Once you know how to read it, the sidewall stops feeling like alphabet soup and starts giving you answers in seconds.

What Is DOT Number on Tires? And Why Buyers Read It First

The “DOT number” is tied to the Tire Identification Number, or TIN. In plain terms, it’s the federal ID molded into the tire sidewall for tracking and recall use. The letters DOT show the tire was marked for sale under U.S. rules, and the code that follows identifies the tire itself.

The piece most drivers care about is the date code at the end. On modern tires, the final four digits show the week and year of manufacture. A tire ending in 3524 was built in the 35th week of 2024. That quick read tells you whether a tire is fresh stock, old stock, or old enough to deserve extra scrutiny before you buy or keep driving on it.

Where To Find It On The Sidewall

You’ll find the DOT marking near the bead area on the sidewall. One side of the tire may show the full code, and the other may show only a partial version. If the last four date digits aren’t there, roll the car a little or check the inward-facing sidewall. Many people miss the date code the first time for that reason.

DOT Number On Tires And What Each Part Means

A full code is made up of sections, not one giant mystery number. Under the federal tire-identification rule, the code includes a plant code, a size code, maker-specific characters, and a date code. You do not need to memorize the regulation to use the code well. You just need to know what each chunk can tell you.

The First Part Points To The Plant

The opening characters identify the plant where the tire was built. That matters most during recalls. If a maker calls back only one plant’s production run, the plant code helps separate affected tires from the rest. For a shopper, it also confirms that four tires said to be a matching set were made in a consistent run.

The Middle Part Narrows Down The Tire

After the plant code comes the tire size code and then a maker-specific code. Those middle characters are mainly for the manufacturer and recall tracing, but they still help you tell one tire from another. Two tires can share the same brand, model, and size printed elsewhere on the sidewall yet carry different TIN details because they came from different runs.

The Last Four Digits Tell The Build Date

This is the section most buyers read first. The first two digits are the production week. The last two are the year. Say the code ends in 1225. That means the tire was built in the 12th week of 2025. On older tires made before 2000, you may run into a three-digit date code instead. If you see that, you’re dealing with an old tire.

DOT/TIN Part	What It Means	Why It Matters
DOT mark	Shows the tire was marked under U.S. road-use rules	Helps confirm you’re reading the right sidewall code
Plant code	Identifies the factory that built the tire	Used to sort affected tires in a recall
Size code	Links the tire to its coded size grouping	Helps separate similar tires in the same brand line
Maker code	Extra characters chosen by the manufacturer	Tracks the build run or tire traits
Week digits	First two digits of the final date block	Shows when in the year the tire was built
Year digits	Last two digits of the final date block	Shows the production year at a glance
Full TIN	Complete code on one sidewall	Needed for the clearest recall and age check
Partial TIN	Shortened code on the other sidewall	Can confuse buyers who think digits are missing

If you’re shopping, this is where the DOT code earns its keep. A salesperson may tell you the tires are “new,” but the sidewall gives you the date in plain numbers. That can save you from paying fresh-tire money for rubber that has already spent years on a shelf.

Why The Date Code Gets So Much Attention

Tread depth is easy to see. Tire age is not. A tire can still have decent-looking tread and still be old enough to make you pause. Rubber changes with time, heat, sun, storage, and use. That’s why buyers, shops, and recall notices lean so hard on the date code.

The date code is also handy when you’re comparing a full set. If three tires end in late 2024 and one ends in 2019, that odd tire has a story. Maybe it was a lone replacement after a puncture. Maybe the seller mixed in an older spare. Either way, the code gives you a starting point for better questions.

• On a used car, it helps you see whether all four tires belong together.
• On a trailer or spare tire, it reveals age that tread wear may hide.
• At a tire shop, it lets you compare stock before installation.
• During a recall search, it helps you match the exact affected range.

If you want to run that recall check yourself, the USTMA Tire Recall Lookup lets you enter the tire identification number to see whether a listed recall matches your tire.

What The DOT Number Cannot Tell You

The DOT code is useful, but it doesn’t tell the whole tire story. It won’t tell you tread depth. It won’t show whether a tire has belt damage, sidewall bruising, a bad patch, or uneven wear from poor alignment. It also won’t tell you whether the tire pressure has been neglected for months.

That’s why a smart tire check uses more than one clue. Read the DOT code, then scan tread wear, sidewall condition, and overall age across the full set. The code tells you where to start. The rest of the tire tells you whether the tire still deserves a spot on the car.

Ending Code	Read It As	What You Learn
0124	Week 1 of 2024	Built early in 2024
1824	Week 18 of 2024	Built in late spring 2024
3524	Week 35 of 2024	Built near the end of summer 2024
4823	Week 48 of 2023	Built late in 2023
1225	Week 12 of 2025	Built in early 2025
399	Pre-2000 three-digit date code	Signals an old tire that needs extra scrutiny

Common Reading Mistakes

Most DOT-number mix-ups come from reading too fast or reading the wrong code on the sidewall. These are the ones that trip people up most often.

• Mixing the DOT code up with the tire size, load index, or speed rating.
• Reading only the outward-facing sidewall and missing the full TIN on the other side.
• Thinking the final four digits are a model code instead of a date code.
• Assuming all four tires on a car were installed at the same time.
• Ignoring a three-digit date code on an old spare or trailer tire.

A good habit is to photograph every tire’s DOT code one by one. That gives you a record for recall checks, warranty claims, and tire-shopping comparisons.

When A Tire Code Should Make You Pause

A DOT number by itself doesn’t condemn a tire. Still, there are moments when it should slow you down and push you to inspect the tire more closely or walk away from the deal.

• The seller says the tires are new, but the date code shows they were built years ago.
• One tire in a set is much older than the other three.
• You find only a partial TIN and the seller can’t show the full code.
• The tire is old and also shows cracks, bulges, vibration, or chronic air loss.

That’s the real value of the DOT number. It gives you a fast, objective clue before you spend money or trust the tire on the road. Read the sidewall, read the last four digits, and you’ll know a lot more about the tire than most buyers do.