How to decode a VIN by hand

A snip.tools guide · runs alongside the VIN decoder

A Vehicle Identification Number looks like a random 17-character jumble, but every position means something. Read it left to right and it tells you who built the vehicle, where, what it is, when it was made and its unique serial — no database required. This guide walks the 17 characters in order, decodes a real VIN by hand, and shows you how to verify the check digit yourself. (To do it instantly instead, paste a VIN into the VIN decoder, which pulls the full build record from NHTSA.)

The 17 characters at a glance

Under the ISO 3779 standard a VIN splits into three sections:

• WMI — World Manufacturer Identifier (positions 1–3). Who built it, and the country the maker's code was assigned in.
• VDS — Vehicle Descriptor Section (positions 4–8). The model, body style, engine and restraint system — a manufacturer-specific code.
• VIS — Vehicle Identifier Section (positions 10–17). The unique part: position 10 is the model year, position 11 the assembly plant, and 12–17 the production serial number.

Position 9, sitting between the descriptor and the serial, is the check digit — a mathematical guard against typos. And one rule spans the whole number: the letters I, O and Q never appear, because they look too much like 1 and 0. Spot one and you know the VIN was copied down wrong.

Positions 1–3: the WMI

The first character sets the region — 1–5 North America, J Japan, K Korea, L China, S–Z Europe, 6–7 Oceania, 8–9 South America. The first two characters together narrow to a country, and the third distinguishes the division or vehicle type. A single maker holds several WMIs, one per plant and country — so the same model can carry a different WMI depending on where that car was assembled. You can look up any three-character code, or browse the common ones by country, in the WMI database.

Positions 4–9: the descriptor and the check digit

Positions 4–8 are the VDS, which each manufacturer defines for itself: body class, engine family, transmission and safety equipment are packed in here, which is why the same five characters mean different things across makers. Position 9 is the check digit, and it is the one part of a VIN you can verify with nothing but arithmetic — here's how.

Verifying the check digit yourself

The check digit ties the other 16 characters together in three steps:

1. Transliterate every character to a number. Digits are themselves. Letters map as A=1, B=2, … H=8, J=1, K=2, … R=9, S=2, T=3, … Z=9 (the pattern restarts a couple of times, and I/O/Q are absent).
2. Multiply each by its positional weight. From position 1 to 17 the weights are 8, 7, 6, 5, 4, 3, 2, 10, 0, 9, 8, 7, 6, 5, 4, 3, 2. Note position 9 — the check digit itself — has weight 0.
3. Sum, then take the remainder modulo 11. A remainder of 0–9 is the expected check digit; a remainder of 10 is written as the letter X. If it matches position 9, the VIN is internally consistent.

A mismatch almost always means a transposed or mistyped character rather than a fraudulent VIN. One caveat: the check digit is mandatory for North American VINs but not universally honoured by imports, so a genuine foreign-market vehicle can "fail" it.

Position 10: the model year

A single character encodes the year, and the code cycles every 30 years. For recent vehicles:

• 2010 = A · 2011 = B · 2012 = C · 2013 = D · 2014 = E · 2015 = F · 2016 = G · 2017 = H
• 2018 = J · 2019 = K · 2020 = L · 2021 = M · 2022 = N · 2023 = P · 2024 = R · 2025 = S · 2026 = T

Letters skip I, O, Q, U and Z. The numbers 1–9 were used for 2001–2009 and come round again for 2031–2039, so a numeric year code is ambiguous on its own — for vehicles over 10,000 lbs GVWR, position 7 being a letter vs. a digit disambiguates the cycle. Position 11 then names the assembly plant using a manufacturer-specific code.

A worked example

Take the VIN 1HGCM82633A004352 and split it:

• 1HG — WMI. 1 = United States; 1HG is Honda's US passenger-car code. A Honda, built in America.
• CM826 — VDS. Honda's descriptor for the model line, body and engine (this one is an Accord sedan).
• 3 — check digit (position 9). Running the arithmetic above, the weighted sum is 311, and 311 mod 11 = 3. It matches — the VIN is consistent.
• 3 — model year (position 10). A numeric code: 2003 (or 2033 next cycle). This is a 2003 model.
• A — plant (position 11), Honda's Marysville, Ohio code.
• 004352 — the sequential production number.

So without any lookup, the raw characters already read: a 2003 Honda Accord, built in the United States, with a valid check digit. A full decode adds trim, engine displacement, horsepower and body class from the manufacturer's records.

What a VIN does and doesn't tell you

Decoding a VIN confirms the vehicle as built — make, model, year, plant and specification. That is exactly what you want when checking a listing matches the car, verifying a unit at a dealer or auction, or filing paperwork. What it does not contain is history: ownership, mileage, title status and accidents live in separate records, so a clean VIN decode is the first step of due diligence, not the whole of it. It also only covers vehicles with a standardized 17-character VIN — off-road and heavy equipment use manufacturer PIN or serial schemes instead.

To try any of this end to end: the VIN decoder validates the check digit in your browser and fetches the full NHTSA build record, and the WMI database resolves just the first three characters to a manufacturer and country.