The vehicle identification number, or VIN, is a car’s fingerprint. Since the 1981 model year, vehicles sold in North America have used a standard 17-character format set by the US National Highway Traffic Safety Administration. Once you know the structure, a VIN tells you a lot before you ever see the car.
The three sections
| Characters | Section | What it tells you |
|---|---|---|
| 1–3 | World manufacturer identifier (WMI) | Where and by whom the vehicle was built. The first character is the region: 1, 4 or 5 for the USA, 2 for Canada, 3 for Mexico, J for Japan, K for South Korea, W for Germany. |
| 4–8 | Vehicle descriptor section | Model, body style, engine, restraint systems and similar attributes, coded by each manufacturer. |
| 9 | Check digit | A calculated digit that catches typos and fake VINs. |
| 10 | Model year | A letter or number for the year: for example L = 2020, R = 2024, S = 2025, T = 2026. |
| 11 | Plant | The assembly plant. |
| 12–17 | Serial number | The vehicle’s unique production number. |
Letters you will never see
The letters I, O and Q are never used anywhere in a VIN, because they are too easy to confuse with 1 and 0. If someone hands you a VIN with an O in it, look again. The year code in position 10 also skips U, Z and the number 0.
How the check digit works
Each letter is converted to a number, each position is multiplied by a fixed weight, and the total is divided by 11. The remainder becomes the ninth character, with a remainder of 10 written as X. Change a single character and the check usually fails, which is why a VIN decoder can flag a mistyped or tampered number instantly.
Where to find it
- On the dashboard, visible through the bottom corner of the windshield on the driver’s side.
- On a label in the driver’s door jamb.
- On the ownership, title, registration and insurance documents. All of them should match the car.
Why it matters when you buy
A decoded VIN confirms the exact model year, trim and engine, so you price the right car. It is also the key to recall checks, history reports and parts lookups. AuctionCalc decodes VINs on its paid plans so buyers can check a listing in seconds, and NHTSA offers a free public decoder for US vehicles.