What is the 17 digit chassis number?
The 17-digit chassis number refers to the Vehicle Identification Number (VIN), a unique alphanumeric code assigned to each road-legal vehicle.
VINs are 17 characters long and can include digits and capital letters (excluding I, O, and Q) to prevent confusion. Since the early 1980s, VINs have been standardized to encode information about a vehicle's origin, attributes, year and production sequence, making it easier to register, service, insure and recall vehicles.
Structure of the VIN
Understanding how a VIN is built helps you read each part with confidence.
- Positions 1–3: World Manufacturer Identifier (WMI) — identifies the country or region of manufacture and the maker
- Positions 4–9: Vehicle Descriptor Section (VDS) — describes attributes such as model, body style, engine; the 9th position is the check digit used to verify the VIN's integrity
- Positions 10–17: Vehicle Identifier Section (VIS) — contains the model year (10th position), manufacturing plant code (11th), and the vehicle's unique serial number (12th–17th)
The three segments together provide a unique fingerprint for every vehicle and are standardized across most markets.
Where to locate and how to decode
Use the following steps and trusted sources to locate and interpret the VIN on your vehicle.
- Where to find: look on the dashboard glass near the windshield on the driver's side; another common place is the driver's door jamb sticker; for some vehicles the VIN is stamped on the engine block or firewall
- How to decode: use the manufacturer's documentation or a reputable online VIN decoder; note that the 10th character indicates model year and letters I, O, Q are omitted to avoid confusion
- Verify with records: cross-check with your vehicle registration, insurance card, and recall databases (NHTSA, manufacturer's site) to ensure accuracy
Reading and validating a VIN can reveal a vehicle's history, but official verification should rely on certified databases or the manufacturer.
Practical notes and limitations
Some vehicles may have VINs stamped in multiple places or on different materials; be sure to read the 17-character sequence as a whole to avoid misreading parts of the code.
Summary
In short, a 17-character VIN serves as the vehicle's global identifier, encoding origin, attributes, year, production plant, and serial number. Reading and validating it helps verify a vehicle's identity and history, and is a standard practice for buyers, insurers, and service providers.
