VIN Validator

VIN: the global vehicle fingerprint defined by ISO 3779

The VIN (Vehicle Identification Number) is the 17-character alphanumeric code that uniquely identifies every road vehicle manufactured since 1981. Standardized by ISO 3779 (structure) and ISO 3780 (WMI assignment), the VIN replaced fragmented national plates and dealer codes, enabling cross-border title transfers, NHTSA recall campaigns, Carfax-style history reports and theft databases like the NICB and Brazilian DENATRAN.

The 17 characters are restricted to digits 0-9 and uppercase letters, with three letters explicitly excluded — I, O and Q — to prevent visual confusion with 1, 0 and 0. The full VIN is stamped on the chassis, dashboard (visible through the windshield), driver door jamb and engine block, plus engraved on body parts in markets like Brazil and the UK to hinder retagging.

Structure: WMI + VDS + VIS

The 17 positions split into three logical sections:

• WMI — World Manufacturer Identifier (positions 1-3): identifies the maker and region of origin.
• VDS — Vehicle Descriptor Section (positions 4-9): encodes body style, engine family, trim and safety features. Position 9 is the check digit.
• VIS — Vehicle Indicator Section (positions 10-17): position 10 is the model year, position 11 is the plant code, and the last 6 are the sequential serial.

Regional WMI prefixes follow ISO 3780: 1-5 United States, 6-7 Oceania, 8-9 South America, A-H Africa, J-R Asia, S-Z Europe. Brazilian WMIs are common in everyday queries: 9BF Fiat Brasil, 9BG GM Brasil, 9BR Hyundai HMB, 9BW Volkswagen Brasil, 9BD Renault Brasil.

The check-digit algorithm (position 9)

Each position is multiplied by a fixed weight, letters are first translated to numeric values (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), and the weighted sum modulo 11 yields the check digit (10 is represented as X).

position:  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17
weights:   8  7  6  5  4  3  2 10  0  9  8  7  6  5  4  3  2
check_digit = (sum of value*weight) mod 11   // 10 -> 'X'

Model year codes (position 10)

The model-year alphabet cycles every 30 years: 1980 = A, ..., 1999 = X, 2000 = Y, 2001 = 1, ..., 2009 = 9, 2010 = A (cycle restart), 2024 = R, 2025 = S, 2026 = T. To disambiguate the two A-Y eras, position 7 is constrained: a letter in position 7 means 2010+, a digit means 1980-2009.

Where the VIN matters

Use cases for VIN decoding and validation:

• History reports: Carfax, AutoCheck, EpicVIN — odometer rollback, accident, salvage and lien records.
• Recall lookup: the free NHTSA vPIC API and the SaferCar portal cross-reference open recalls.
• Insurance underwriting: VIN drives premium pricing through equipment level and theft risk.
• Theft recovery: NICB (US), DENATRAN/SINIVEM (BR), Interpol Stolen Motor Vehicles database.
• OEM warranty and parts catalog: dealer ECUs decode the VIN to select correct parts.
• Import compliance: customs verifies WMI, year and emission compatibility.

Fraud, VIN cloning and limits of online validators

VIN swapping — physically restamping or replacing tags from a stolen car with those of a wrecked donor — is the most common automotive identity fraud. Although harder than plate cloning (engraving on chassis and glass etching), it remains widespread. In Brazil it falls under the Codigo Penal art. 311; in the US under federal 18 USC 511. This validator confirms only the ISO 3779 algorithm: a VIN can pass the check digit and still be fictitious or cloned. For authoritative ownership, query NHTSA vPIC, your DMV/DENATRAN, or paid services such as Carfax.

FAQ

Is this validator reliable? Yes — it implements the full ISO 3779 check-digit calculation, including the letter-to-digit translation table. Any VIN that fails here is malformed.

Where can I look up a VIN for free? The NHTSA vPIC public API (vpic.nhtsa.dot.gov/api) returns manufacturer, model, year, body style and powertrain at no cost.

Why does my VIN have no check digit? Vehicles built before 1981 and some pre-2004 European cars do not follow the full ISO 3779 mandate, so the check-digit slot may carry any character — the validator will flag it as malformed.

Can a VIN really be forged? Physically yes, but it is significantly harder than plate cloning because the VIN is stamped on the chassis, engine block, dashboard and often etched into the windshield and door glass.

Why are I, O and Q forbidden? To prevent visual confusion with 1, 0 and 0 — critical for handwritten reports, weathered tags and OCR scanners.