Decoding Your Vehicle Identification Number
Every car, truck, and motorcycle manufactured since 1981 carries a unique 17-character fingerprint: the Vehicle Identification Number, or VIN. You’ll find it on a riveted placard at the base of the dashboard, a label on the driver’s door jamb, or in your registration documents. Far from a random string of characters, each position in a VIN encodes specific information about where the vehicle was built, who made it, what it is, and when it rolled off the assembly line.
The modern VIN standard was established by the International Organization for Standardization (ISO) in 1979 under ISO 3779 and adopted by manufacturers starting in the 1981 model year, when NHTSA mandated that all road vehicles sold in the United States carry a standardized 17-character VIN. The format uses 17 alphanumeric characters — notably excluding the letters I, O, and Q to avoid confusion with the digits 1, 0, and 9, as specified in 49 CFR 565.13.
Hover over (or tap) each character below to see exactly what it encodes.
Explore a VIN
Note: Position 9 (the check digit) is formally part of the VDS per 49 CFR 565.15, but is highlighted separately here because of its unique role.
Hover over or tap each character to learn what it means. Use Tab to navigate with a keyboard.
Try Your Own VIN
Paste or type a 17-character VIN to decode it interactively.
The Three Major Sections
Per 49 CFR 565.15, every VIN is divided into three sections: the WMI (positions 1–3), the VDS (positions 4–9, including the check digit), and the VIS (positions 10–17). In the interactive display above, we highlight the check digit separately because of its special verification role — but officially it belongs to the VDS.
World Manufacturer Identifier (WMI) — Positions 1–3
The first three characters identify who made the vehicle and where. Position 1 narrows it down to a country or region. Position 2 identifies the manufacturer. Position 3 further specifies the vehicle type or manufacturing division. Together, these three characters form the World Manufacturer Identifier defined by ISO 3780, and are assigned by the Society of Automotive Engineers (SAE), unique to each manufacturer worldwide.
A special case: if a manufacturer produces fewer than 1,000 vehicles per year, position 3 is set to 9, and positions 12–14 are used as an additional manufacturer identifier (49 CFR 565.15).
Vehicle Descriptor Section (VDS) — Positions 4–9
These six characters describe what the vehicle is and include a verification check digit. The exact meaning of positions 4 through 8 varies by manufacturer — there is no universal standard for these positions. However, they typically encode attributes like:
- Body style (sedan, coupe, SUV, convertible)
- Restraint system and airbag type
- Gross vehicle weight rating (GVWR)
- Model line or series
- Engine type (especially position 8)
- Motor or battery type for electric vehicles — as EVs have become widespread, manufacturers have adapted these positions to encode powertrain details like motor configuration and battery capacity
Position 9 is the check digit, which is covered in detail below.
Vehicle Identifier Section (VIS) — Positions 10–17
The final eight characters tell you when and where a specific vehicle was built, plus its unique production number. Position 10 encodes the model year, position 11 identifies the assembly plant, and positions 12–17 form a sequential production number. The last four digits (positions 14–17) must always be numeric (49 CFR 565.15).
The Check Digit — Position 9
The last position of the VDS is a single character with a unique job: data integrity. The check digit’s primary purpose is catching transcription errors — typos, transposed characters, and data entry mistakes that would otherwise go unnoticed. As an additional benefit, it also helps detect VIN fraud: if someone alters any character in a VIN, the check digit will no longer match, revealing the tampering.
The check digit is calculated using a weighted sum of all other 16 characters, converted to numeric values through a transliteration table, then taken modulo 11. The result is a digit from 0–9, or the letter X (which represents 10). The full algorithm is specified in 49 CFR 565.15 (Tables III, IV, and V). This system is required in North America and China, but not in Europe.
How the check digit is calculated
Step 1: Convert each letter to a number using this transliteration table (digits keep their face value):
| A | B | C | D | E | F | G | H |
|---|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| J | K | L | M | N | P | R |
|---|---|---|---|---|---|---|
| 1 | 2 | 3 | 4 | 5 | 7 | 9 |
| S | T | U | V | W | X | Y | Z |
|---|---|---|---|---|---|---|---|
| 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
Step 2: Multiply each position’s value by its weight factor:
| Pos. | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Wt. | 8 | 7 | 6 | 5 | 4 | 3 | 2 | 10 | 0 | 9 | 8 | 7 | 6 | 5 | 4 | 3 | 2 |
Position 9 has weight 0 because it’s the check digit itself.
Step 3: Sum all the products and take the result modulo 11.
Step 4: If the remainder is 10, the check digit is X; otherwise it’s the remainder itself (0–9).
Model Year Codes — Position 10
The model year is encoded as a single character using a 30-year rotating cycle, defined in Table VII of 49 CFR 565.15. The cycle uses letters A–Y (skipping I, O, Q, U, and Z) followed by digits 1–9, then repeats. To tell which 30-year cycle a vehicle belongs to, check position 7: if it’s numeric, the vehicle is from the 1980–2009 cycle; if it’s alphabetic, it’s from the 2010–2039 cycle. The cycle restarts with A = 2040.
Note: since the 17-character VIN standard only took effect for the 1981 model year, the 1980 codes in this table apply only to a small number of early adopters. Pre-1981 VINs varied widely in length and format.
| Code | Year | Code | Year | Code | Year |
|---|---|---|---|---|---|
| A | 1980 / 2010 | L | 1990 / 2020 | 1 | 2001 / 2031 |
| B | 1981 / 2011 | M | 1991 / 2021 | 2 | 2002 / 2032 |
| C | 1982 / 2012 | N | 1992 / 2022 | 3 | 2003 / 2033 |
| D | 1983 / 2013 | P | 1993 / 2023 | 4 | 2004 / 2034 |
| E | 1984 / 2014 | R | 1994 / 2024 | 5 | 2005 / 2035 |
| F | 1985 / 2015 | S | 1995 / 2025 | 6 | 2006 / 2036 |
| G | 1986 / 2016 | T | 1996 / 2026 | 7 | 2007 / 2037 |
| H | 1987 / 2017 | V | 1997 / 2027 | 8 | 2008 / 2038 |
| J | 1988 / 2018 | W | 1998 / 2028 | 9 | 2009 / 2039 |
| K | 1989 / 2019 | X | 1999 / 2029 | ||
| Y | 2000 / 2030 |
Where to Find Your VIN
Your VIN can be found in several places on the vehicle:
- Dashboard — look through the windshield at the driver’s side base of the dashboard
- Driver’s door jamb — on a sticker or plate when you open the driver’s door
- Vehicle registration and title documents
- Insurance card or policy documents
- Engine block — stamped on some vehicles
Sources
The information in this article is drawn from the following primary and secondary sources:
- 49 CFR Part 565 — Vehicle Identification Number Requirements
- The U.S. federal regulation that governs VIN format, content, and the check digit algorithm. Full text on eCFR. Key sections: §565.13 (general requirements, allowed characters) and §565.15 (content requirements, transliteration tables, weight factors, model year codes, low-volume manufacturer rule).
- ISO 3779:2009 — Road vehicles — Vehicle identification number (VIN) — Content and structure
- The international standard specifying the 17-character VIN format. ISO catalog page.
- ISO 3780:2009 — Road vehicles — World manufacturer identifier (WMI) code
- The international standard defining the first three characters of the VIN. ISO catalog page.
- NHTSA — Vehicle Identification Number Requirements (Federal Register, 2008)
- The Federal Register document for the 2008 VIN rule amendment, which includes extensive historical background on the 1978 final rule mandating 17-character VINs from the 1981 model year onward. Federal Register entry.
- SAE J1044 — World Manufacturer Identifier
- The SAE standard governing the assignment of WMI codes to manufacturers, as referenced in 49 CFR 565.16. SAE catalog page.
- NHTSA Product Information Catalog — vPIC VIN Decoder
- The official U.S. government VIN decoding tool and API, using manufacturer-submitted data. Web decoder · API documentation.
- Wikibooks — Vehicle Identification Numbers (VIN codes)
- A community-maintained reference with worked examples of the check digit algorithm and WMI tables. Check digit walkthrough.