A Vehicle Identification Number (VIN) is a standardized 17-character code that uniquely identifies a road vehicle. VINs are used worldwide to track a vehicle's build, specifications, compliance, recalls, and registration. To avoid confusion with digits, the letters I, O, and Q are not used anywhere in a VIN (NHTSA, 49 CFR Part 565).
VINs have existed since the 1950s, but the format varied by maker until the United States standardized the 17-character format for the 1981 model year (FAXVIN VIN Decoder). Modern VINs are defined by ISO standards (ISO 3779 / ISO 3780) and implemented with regional specifics (e.g., U.S. Part 565 rules).
VIN Structure at a Glance
- WMI (World Manufacturer Identifier): positions 1–3.
- VDS (Vehicle Descriptor Section): positions 4–8. Vehicle attributes (model/series/body/engine, per maker's scheme).
- Check Digit: position 9.Mathematically validates the VIN (North America).
- VIS (Vehicle Identifier Section): positions 10–17. Model year (10th), plant (11th), and serial sequence (12–17).
World Manufacturer Identifier (WMI)
The first three characters identify the manufacturer and region. For very low-volume manufacturers, the third character may be "9", and the manufacturer identifier continues in positions 12–14.
Note: ISO 3780 specifies the "9" rule for makers producing under defined low-volume thresholds; U.S. regulations also define a low-volume category in Part 565.
Vehicle Descriptor Section (VDS)
Positions 4–8 describe the vehicle's type and key attributes (platform, body style, restraint systems, engine where applicable). Each manufacturer defines this mapping within regulatory bounds.
Check Digit (9th Character)
In the U.S. and Canada, the 9th character is a mandatory check digit computed by an algorithm defined in regulation. If the computed value is 10, the check digit appears as "X". This protects against common transcription errors (NHTSA Part 565 rule text).
Vehicle Identifier Section (VIS)
Positions 10–17 uniquely identify the vehicle as built:
- 10th character = Model Year (North American scheme). See year-code tables used by authorities such as NSAI.
- 11th character = Assembly Plant (maker-defined).
- 12th–17th = Serial sequence. In the U.S., for passenger cars, MPVs and light trucks ≤10,000 lb GVWR, the last five (5) characters must be numeric (NHTSA Part 565).
VIN Length & Allowed Characters
A VIN is always 17 characters and uses only uppercase letters and digits from these sets: ABCDEFGHJKLMNPRSTUVWXYZ and 0123456789. The letters I, O, Q are excluded to prevent confusion with 1 and 0 (NHTSA).
Where to Find Your VIN
- Dashboard (driver side): visible through the windshield at the base of the left A-pillar.
- Driver-side door/door jamb: on a certification label.
- Official documents: registration, title, or insurance.
See official guidance and run an official decode at NHTSA VIN Decoder or learn more via FAXVIN Location Guide.
Why VINs Matter
- Safety & recalls: check for open recalls using your VIN on NHTSA.gov/Recalls.
- Compliance & records: VINs tie to emissions/safety compliance, titling, and theft recovery.
- Parts & service: correct parts depend on exact build (engine, restraints, trim).
Standards & Regulations
Core references: ISO 3779 / ISO 3780 and 49 CFR Part 565 (NHTSA). The EU implements VIN based on ISO standards; national bodies such as NSAI administer WMI assignments.