ISO 3779
The international standard that defines VIN structure (17 characters, three sections).
ISO 3779 is the international standard, first published by the International Organization for Standardization in 1977 and most recently revised in 2009, that defines the structure of the modern Vehicle Identification Number. Adoption by US regulators (NHTSA Federal Motor Vehicle Safety Standard 115 in 1981) made the 17-character VIN universal across world markets — before then, manufacturers used their own ad-hoc serial numbers ranging from 5 to 13 characters with no shared meaning between brands.
ISO 3779 specifies that every VIN must be exactly 17 characters, must use only the digits 0–9 and the letters A–Z excluding I, O and Q (to avoid confusion with the digits and with Q-shaped characters), and must split into the WMI (positions 1–3), VDS (4–9) and VIS (10–17) sections. A companion standard, ISO 3780, governs how WMI codes are assigned to manufacturers.
Some pre-1981 vehicles in collector circles still carry their shorter original VINs and require special handling at title and auction time — modern VIN-lookup tools (including ours) only decode 17-character ISO 3779 VINs.