VIN Number Decoding: What is a VIN?

What Is a VIN Number?

Before 1981, no standardization of VINs on American model cars and trucks existed. Vehicle manufacturers could have used 8 digits, 10 digits, 25 digits, or really any number of digits they wanted. In 1981, the National Highway Traffic Safety Administration required all car manufacturers to use 17 digits. Each number within that 17 digit VIN meant something specific about that car. Well, except for one of those digits, but we'll get into that later.

Quick Facts about VIN Numbers

Letters I, O, and Q

The letters "I," "O," and "Q" are not used in VINs from 1981 to today because they can be easily confused with the numbers "one" and "zero."

VIN vs VIN Number

You may see "VIN Number" throughout this page. I realize that saying "Vehicle Identification Number...Number" is silly, but it sure rolls off the tongue easier. In the real world, that is how people say it, and being a real person... well, you get the point.

10th Digit of VIN

For the 10th digit of the VIN number, letters "U" or "Z" are not used. The NHTSA decided it, and that's just the way it is.

Foreign Cars: VIN Info in Different Order

The last thing worth noting is that some foreign car manufacturers switch around these VIN numbers slightly. On many Volkswagens for example, the 3rd through 8th digits are in a different order than the American brand cars and trucks. They still have the same VIN information but in slightly different spots. Typically the engine, vehicle series, body type, restraint system, and model are the ones to watch out for. The country, make, check digit, year, plant, and serial number are usually in the same positions regardless of the vehicle manufacturer.

How to Decode a VIN Number

The first three digits of the VIN are known as the "WMI", which is an acronym for "World Manufacturer Identifier". That encompasses the country of origin, the manufacturer, and the division that the vehicle is built for.

1st Digit: This digit designates the country where the vehicle was made. In the example above, the first digit (1) means "United States"; if it was "J", it would mean Japan.

2nd Digit: The 2nd digit designates the manufacturer that built the vehicle. This doesn't always mean the "make" of the car (like GMC), because companies like General Motors have many different divisions. They have Chevy, Buick, and GMC, along with many others. In the example above, the second VIN digit would mean "General Motors".

3rd Digit: The 3rd digit is the division of the larger manufacturer. In the case of General Motors, the division would be the more specific Buick, Cadillac, etc. So, in the example above, the "N" happens to mean "Chevy".

Digits "four" through "eight" are called the "Attributes" of the VIN. They include information like safety, engine size, body style, and vehicle series.

4th Digit: The 4th digit is safety, braking and suspension. For example, if you have a special option, heavy-duty truck with eight-lug wheels or a towing package, this digit will indicate the vehicle has a special suspension and brake package. It might also reference a specific safety restraint package, like if the vehicle had a two vs. eleven airbag option, for example.

5th Digit: The 5th digit, in this case, "S," which is the series of the vehicle. In the 1980s, for example, General Motors built full-size C and K series trucks, along with R and V series. The C/K was a different body style than the R/V. The "C" and "R" were designations for two-wheel drive. The "K" and "V" were designations for four-wheel drive. These letters would be found as the fifth digit of the VIN on these trucks. It was/is important when ordering parts, because a "1988 Chevy Truck" could mean a variety of things depending on what that letter is. In this picture above, we have an S series, which happens to be an S-10 series truck. There was also a T series at the same time.

6th & 7th Digits: The 6th and 7th denote the body style. So if the vehicle is a convertible, a two-door, four-door, or wagon, it is defined in these two digits.

8th Digit: The 8th digit, in this case, a "Z," is one of my personal favorites. It's the engine size! So if you were to go to a junkyard, this digit is really helpful for vehicles that had two different engines during the same year. An S10 Truck or an S10 Blazer are perfect examples of this. Both of these trucks could have come with a 4.3 liter that was a Z series engine or a W series engine. Both engines were 4.3-liters, but they had different parts attached to them. Buying parts for these engines is always interesting and this digit is what makes it that way.

9th Digit: The 9th digit is called a check digit. It is called a check digit because the purpose of it is to check the rest of the VIN number for legitimacy. This is done by putting the VIN digits through some complex math. At the end of the equation, hopefully, come out with the number that is in the ninth spot. If it comes out as something other than that, you know that the VIN Number is made up.

10th Digit: The 10th digit is the year, which is helpful if you're in a junkyard or showing off to your friends. You can easily figure out which years match up to which letters and which numbers with the chart below. Print it out and throw it into your wallet. You might thank us someday.

In today's example, the tenth digit is "M", so if you check out the chart, you'll see that "M" is 1991. This is great for junkyards because you can walk up to a VIN number and say "Hey this is a VIN J, which means it's a 1988".

VIN Number Year Chart

11th Digit: The 11th digit is the manufacturing plant. As you can guess, that's where the vehicle is made! This doesn't often matter so much unless you are talking about certain cars that have major followings. Corvettes are a great example. Many, many Corvettes were made in Bowling Green, Kentucky. There is even a museum there! So whenever you talk about Corvettes, Bowling Green inevitably comes up. The eleventh digit of the VIN number is the one that confirms the plant at which the vehicle was built. It might be Lansing, Michigan; Detroit, Michigan; or somewhere in Illinois. Car manufacturers have plants all over the world.

The Last Six Digits: The last six digits are the production line numbers. Most vehicle manufacturers start with the number 100001 as a starting point. This is normally not a super important number as far as buying auto parts goes unless you have a vehicle that changed production specifications halfway through a production run. So, you might have a vehicle that had different mirrors if it was built in April of 2004, then if it were built in August of 2004. If you have one of those vehicles, you need to know where it was in the production line, which is where these last six digits become important.

How to Find Option Codes

In addition to VINs there are also a plethora of option codes located somewhere in the interior of every vehicle. Long ago, they used to be actual printed pieces of paper, that were stuffed into the seat springs. In modern cars, it is usually a printed sticker in the glove compartment, console, or trunk. When you combine the VIN number with the option codes, you get the entire genetic makeup of the vehicle from top to bottom.