RV tire date code decoder

The last four digits of the DOT code

Read it

Enter the last four digits of the DOT code, like 0308.

Where the four digits are

The code is moulded into the sidewall and starts with the letters DOT. The four digits at the very end are the date. NHTSA describes the whole number:

"This number begins with the letters DOT and indicates that the tire meets all Federal standards. The next two or three numbers or letters are the plant code where the tire was manufactured. The last four numbers represent the week and year the tire was built. For example, the numbers 3107 means the 31st week of 2007."

Two things catch people out. The code may be on only one side of the tire, so if you cannot find it on the outside, look on the inner sidewall. And the date digits are the last four, not the first four, which are the plant code.

How the four digits read

The first two are the week of the year and the last two are the year, which is how the regulator states it:

"The last four digits of the TIN indicate the week and year the tire was made. If the TIN reads 0308 it was made in the third week of 2008."

So 0308 is the third week of 2008, and 3107 is the thirty-first week of 2007.

What the age is for

Tires age whether or not they wear, and the age is why this decoder exists. NHTSA puts it plainly: "As tires age, they are more prone to failure. Some vehicle and tire manufacturers recommend replacing tires that are six to 10 years old, regardless of treadwear."

That is a recommendation from the tyre and vehicle makers rather than a legal limit, and it is stated here as they state it. Your own tire's maker and your trailer's manual are the two documents that decide your number, and both are worth reading before a long trip rather than after a blowout.

What this tool will not tell you

It reads the date. It does not judge the tire. Tread depth, cracking, bulges, repairs and how the tire has been stored all matter as much as the number, and none of them are visible in four digits. A tire inside the makers' age window can still be unsafe, and one past it can still look perfect.

And a four-digit code only exists on tires built from 2000, because the format changed then. If the code on your sidewall ends in three digits rather than four, that is a tire from before the change, and the answer is a tire shop rather than a decoder.

By OriginRV. Last updated on Oct 2, 2026.