Vehicle Identification

In the beginning motor vehicles were simply marked, if at all, with production serial numbers.  Around August 1964 American manufacturers began to code vehicle model and year information into the number, as well as the serial number. Typically the first two digits represented the model, the third the year, and the fourth through ninth were the serial number. If more than 999,999 units were produced, a 10-digit number was used, with the fourth digit a "1". In 1970 a 10-digit VIN became standard. 

In February 1977 the ISO issued the first version of ISO 3779, an international standard for VIN's.

In the United States, the National Highway Traffic Safety Administration required that, beginning with the 1981 model year, all over-the-road vehicles must be sold with a 17-character VIN (49 CFR Part 565, Vehicle Identification Number Requirements). The NHTSA's requirements were more stringent than those of the ISO, but compatible with them. In 1987 NHTSA required that the VIN be applied to major parts of car models with a history of high theft rates, to deter trade in stolen parts, and in 1994 the Theft Prevention Standard was amended to require the VIN on major parts of light trucks and MPV's as well.

The VIN is made up solely of the numerals 1 through 0 and capital letters A to Z, not including the letters I, O, and Q, which are too easily mistaken for numerals. Spaces, dashes and symbols are not allowed.

The VIN consists of three sections (in North America, the check digit, position 9, is considered a separate section, and the designations WMI, VDS and VIS are not used):

World Manufacturer Identifier (WMI)

The first three digits of the VIN identify the country of origin and the manufacturer. The VIN begins with a code identifying the country of manufacture. For example, cars with VINs beginning with 1, 4 or 5 were built in the United States. A code for the company that manufactured the car follows. (Many companies have more than one WMI, reserving different WMIs, for example, for different model lines.) If the manufacturer builds fewer than 500 vehicles per year, the 3rd place holds a “9”.

The WMI is described in ISO standard 3780. WMI's for the United States are issued by the SAE, as the U.S. representative of the ISO for this purpose, and under a contract with the Department of Transportation.

Vehicle Descriptor Section (VDS)

These digits may be used by the manufacturer to describe the engine, body, transmission, safety features and emission control systems.  They are not required in the EU. Each manufacturer makes up its own set of codes for the meaning of characters in these places.

4 For cars, MPV's and light trucks, these positions hold an alphabetic character. for example, engine
6 For cars, MPV's and light trucks, these positions hold a numeric character.
7 for example, body and transmission
8   for example, restraint
9 American and Canadian regulations require that the 9th place hold a check digit The check digit is calculated from all the other characters in the VIN, both numerical and alphabetical, and will be a numeral from 0 to 9, or the character X. Later the check digit can be automatically recalculated, for example by a Dept. of Motor Vehicles to detect an error in copying. If the newly-computed digit does not match the character in position 9, an error has occurred.
      In cars made for the European market, this position may be used for other purposes.  Volvo, for example, uses it to describe the type of transmission.

Vehicle Identifier Section (VIS)

10 If a year code is used, the standard recommends it be in this position. In North America a year code is required. The European Union does not. The letter U and the numeral zero are not used in year codes. For a list of year codes, see  
11 If a code identifying the factory where the vehicle was made is used, the ISO standard recommends it be in this position.  
12 Serial number for manufacturers producing more than 500 vehicles per year. For cars, MPVs and light trucks the last five characters must be numeric. For all other types of vehicles the last four characters must be numeric.  Used for the second part of the WMI for manufacturers of fewer than 500 vehicles per year.
15 Serial number for manufacturers producing fewer than 500 vehicles per year. Numeric characters only.


A number of interactive VIN interpreters are available on the web, for example: 

ISO 3779:1983. Road Vehicles -- Vehicle Identification Number (VIN) -- Content and Structure.

SAE - J187 - Truck Vehicle Identification Numbers.
SAE – J218 – Passenger Car Identification Terminology.
SAE – J272 – Vehicle Identification Number Systems.
SAE – J273 – Passenger Car Vehicle Identification Number System.
SAE – J853 – Vehicle Identification Numbers.
SAE – J1108 – Truck and Truck Tractor Vehicle Identification Number Systems.
SAE – J1044 – World Manufacturer Identifier.
SAE – J1229 – Truck Identification Terminology.
SAE – J1877 – Recommended Practice for Bar-Coded Vehicle Identification Number Label.

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