Understanding VINs

VIN structure and standards — what the 17 characters mean.

A Vehicle Identification Number (VIN) is a unique 17-character code that identifies a specific vehicle. Based on ISO standards 3779 and 3780, VINs are crucial for accurate vehicle identification and tracking.

VIN standards

VINs follow standards established by the International Organization for Standardization (ISO):

ISO 3779 defines the VIN structure
ISO 3780 establishes the World Manufacturer Identifier system

Different regions have compatible but distinct implementations:

Region	Format
North America (>2,000 vehicles/year)	WMI + Vehicle attributes + Check digit + Model year + Plant code + Sequential number
North America (≤2,000 vehicles/year)	WMI + 9 + Vehicle attributes + Check digit + Model year + Plant code + Manufacturer ID + Sequential number
European Union (>500 vehicles/year)	WMI + Vehicle characteristics + Vehicle identification
European Union (≤500 vehicles/year)	WMI + 9 + Vehicle characteristics + Manufacturer ID + Vehicle identification

VIN structure overview

Section	Positions	Meaning
WMI	1–3	World Manufacturer Identifier — region and manufacturer codes
VDS	4–8	Vehicle Descriptor Section — vehicle attributes and platform
Check digit	9	Validation digit (required in North America and China)
VIS	10–17	Vehicle Identifier Section — unique vehicle details

text

1HD1KB4157Y123456
│││││││││││└──────┘
│││││││││││ Serial number (12-17)
│││││││││││
││││││││││└─ Plant code (11)
│││││││││└── Model year (10)
│││││││└──── Check digit (9)
││││││└───── Engine type (8)
│││││└────── Body type (7)
││││└─────── Series (6)
│││└──────── Restraint system (5)
││└───────── Platform (4)
│└────────── Make (2-3)
└─────────── Region (1)

World Manufacturer Identifier (WMI)

The first three characters identify the manufacturer and region. For manufacturers producing fewer than 1,000 vehicles per year, the third digit is '9', with additional identification in positions 12–14.

Region codes (first character)

First character	Region
A–C	Africa
J–R	Asia
S–Z	Europe
1–5, 7	North America
6	Oceania
8–9	South America

Common examples:

1, 4, 5, 7: United States
2: Canada
3A–3W: Mexico
J: Japan
K: Korea
L: China
W: Germany
VF–VR: France
SA–SM: United Kingdom

Vehicle Descriptor Section (VDS)

Characters 4–9 describe the vehicle's attributes and include a check digit. The VDS format varies by manufacturer but typically includes:

Position	Content
4	Vehicle line, platform, or model series
5	Safety and restraint system type
6–7	Body style and series information
8	Engine type and size
9	Calculated validation digit

Vehicle Identifier Section (VIS)

The final eight characters (10–17) uniquely identify the specific vehicle:

Position	Content
10	Single character encoding the vehicle's model year
11	Manufacturing plant identifier
12–17	Production sequence number (12–14 double as manufacturer ID for small manufacturers)

Model year encoding

The 10th position encodes the model year using a repeating pattern (letters exclude I, O, Q):

text

Code Year  Code Year  Code Year
A    2010  L    2020  Y    2030
B    2011  M    2021  1    2031
C    2012  N    2022  2    2032
D    2013  P    2023  3    2033
E    2014  R    2024  4    2034
F    2015  S    2025  5    2035
G    2016  T    2026  6    2036
H    2017  V    2027  7    2037
J    2018  W    2028  8    2038
K    2019  X    2029  9    2039

The same codes covered 1980–2009 in the previous cycle (A–Y for 1980–2000, 1–9 for 2001–2009).

Check digit calculation

The 9th position contains a check digit that validates the VIN:

Transliterate letters to numbers:

text

A=1 B=2 C=3 D=4 E=5 F=6 G=7 H=8 J=1
K=2 L=3 M=4 N=5 P=7 R=9 S=2 T=3 U=4
V=5 W=6 X=7 Y=8 Z=9

Apply weights per position:

text

Position: 1  2  3  4  5  6  7  8  9  10 11 12 13 14 15 16 17
Weight:   8  7  6  5  4  3  2  10 0  9  8  7  6  5  4  3  2

Calculate: sum the products and divide by 11. The remainder is the check digit (X if 10).

The letters I, O, and Q are never used in VINs to avoid confusion with numbers.

Decoding VINs with the API

The v2 surface decodes a VIN to its graph identity — display names, entity refs, nano/squish grains, and links to the instrument, recalls, and listings for that vehicle:

bash

curl "https://api.cardog.app/v2/vin/1HGCM82633A123456" \
  -H "x-api-key: $CARDOG_API_KEY"

See the VIN reference for the full response shape, batch decoding, and the VIN → recalls / listings / instrument bridges.

Where to find a VIN on the vehicle

Lower corner of the windshield (driver's side)
Under the hood near the latch
Front end of the vehicle frame
Driver's side door pillar