How to check a VIN before you bid at a US auction

The VIN is the one detail that follows a car through every owner, repair and auction. Before you bid at Copart or IAAI, take a few minutes to check a VIN properly: read what it says about the car, make sure it was copied correctly and look at what happened the last time the car was sold.

What the 17 characters of a VIN mean

Cars built for North America since the early 1980s carry a 17 character VIN. It uses digits and capital letters, but never I, O or Q, so nobody can confuse them with 1 and 0. The characters are read in groups:

1. Positions 1 to 3, the maker. The country or region, the manufacturer and often the vehicle type.
2. Positions 4 to 8, the model. Model, body, engine or series, in the maker's own code.
3. Position 9, the check digit. 0 to 9 or X, calculated from the other 16 characters.
4. Position 10, the model year. The codes repeat every 30 years, so read it with the rest of the car.
5. Position 11, the plant. The factory where the car was assembled.
6. Positions 12 to 17, the serial number. The car's own production number.

You do not need to memorise the codes. What matters is that the year, make and model in the listing agree with the VIN, and that the VIN plate in the photos matches the listing.

How to check a VIN for typos with the check digit

Every character of the VIN gets a value, letters through a fixed table, and every position has a weight. The values are multiplied by their weights, added up and divided by 11. The remainder must equal the ninth character, with 10 written as X.

So a single wrong character usually breaks the VIN. Type an 8 instead of a B, or swap two characters, and the check digit no longer matches. A VIN that fails the check is almost always a typo, yours or in the source you copied.

Keep the limits in mind:

• The check digit is required on cars built for North America. Cars made for other markets, such as some Korean cars on Encar, may not use it.
• A valid check digit only means the VIN is well formed. It does not prove the car is what the listing says.
• Some letters share the same value, so a rare typo can still pass.

See the photos and earlier sales of the car

Once the VIN is right, look at the car itself. Search any VIN on Bidpier and the lot page shows every auction photo, the primary and secondary damage, the title details, mileage, keys, yard location, sale date and current bid.

Below the current lot you will find every earlier sale of the same VIN, with the bid each one ended on. This is often the most useful part:

• A car that sold a few months ago and is back may have been repaired, or may have a problem the last buyer did not want to fix.
• Compare the mileage between sales. It should only go up.
• Compare the damage labels and photos. New damage or a missing part tells you something happened in between.
• The earlier final bids give you a feel for what buyers paid for this exact car.

To judge the price beyond this one car, open the auction prices statistics for its make and model, or browse Copart lots and IAAI lots of the same model.

Check it on Bidpier

Bidpier is free and needs no account. Paste a VIN or lot number into the search box, read the earlier sales, then compare similar cars in the catalog. Bidpier does not sell cars or run auctions: to bid, use a licensed broker or the auction itself.