The VIN (Vehicle Identification Number) is a car’s 17-character “social security number”. From it you can read history, origin, factory equipment and - most importantly when buying - whether the car is stolen, accident-damaged, or whether the details match. Checking the VIN is the first thing I do with any car, before I even drive out to inspect it.

Where to find the VIN

The VIN is in several places (and the fact that it’s in several places is what lets you detect fraud):

Registration document - the VIN field.
Windshield, bottom on the driver’s side - a plate visible from outside.
B-pillar (by the driver’s door hinge) - a sticker.
Engine bay - stamped on the body or on the data plate.
Under the seat / carpet on the driver’s side - in many cars stamped into the floor.
Insurance policy, service invoices.

First test: is the VIN identical in every location. A difference of even one character = an alarm signal (re-stamped number, a car assembled from two, stolen).

How to read a VIN (basics)

17 characters, no letters I, O, Q (to avoid confusion with 1 and 0):

Characters 1-3 (WMI) - manufacturer and country. E.g. WBA = BMW Germany, WVW = VW passenger, SAL = Land Rover.
Characters 4-9 (VDS) - model, body type, engine, sometimes a check digit.
Character 10 - the model year (e.g. L=2020, M=2021, N=2022, P=2023, R=2024, S=2025). Check it matches the advertised year.
Character 11 - assembly plant.
Characters 12-17 - the unit’s serial number.

Simplest quick test: the model year (character 10) must match the stated year. A mismatch = someone is fiddling.

What you can check by VIN - for free

National vehicle history database (e.g. historiapojazdu.gov.pl in Poland) - mileage from technical inspections, number of owners, registration dates, status. The most important free source.
Service recalls - entering the VIN on the manufacturer’s site shows whether the car had factory defects covered by free repair (and whether it was done).
Stolen vehicle databases - national and Interpol.
Google: “VIN [number] copart” or “iaai” - if the car went through a US salvage auction, it often shows up with a damage map and photos from before the repair.

What you can check by VIN - paid

carVertical, autoDNA and similar - aggregate data from many countries: mileages, damage, auction photos, foreign history. Paid, but often worth it for an imported car.
Digital service history at the brand dealer - by VIN, the dealer (BMW, VAG, Mercedes…) will print every service visit with mileages. Hard to fake, excellent for detecting a rolled-back odometer.

Red flags when checking a VIN

VIN differs across locations on the car - re-stamped number, assembled car.
VIN plate riveted with non-factory rivets, glue marks, crooked - swapped.
Model year (character 10) ≠ the year in the listing.
Seller hides the VIN, won’t share it, “I’ll give it when you arrive” - a classic move so you can’t check before the visit.
WMI doesn’t match the brand (e.g. listing says “BMW” but the VIN starts with another maker’s code).
Car deregistered / “for repair” in the database while listed as roadworthy.

How I do it in practice

Before setting off: I take the VIN from the listing (an honest seller provides it upfront) and check the history database + Google for US auctions + recalls. This filters out 30-40% of cars without leaving home.
On site: I compare the VIN from all locations on the car - whether they match each other and the registration document.
For an imported car: I buy a foreign database report, because local history only begins at registration in the country.

Instead of clicking through five databases separately, in MotoPPI you paste a listing link or just the VIN, and the report combines history, origin, salvage auctions and flags in one place - with a ready checklist of what to verify on site at the car.

The most common question: is the VIN alone enough?

No. The VIN tells you history and origin - a huge part of the decision. But it won’t show the technical condition “here and now” (paint, cold start, play, corrosion). VIN check + on-site inspection is the complete picture. The VIN filters out traps before you get in the car; the inspection closes the decision.