If you’re shopping for a used car, one of the first things you should do when finding a vehicle is check the Vehicle Identification Number (VIN). A VIN can tell you what a car is — and, just as importantly, what it’s been through.

What a VIN number is (and why it matters)

A VIN is a standardized 17-character string of letters and numbers assigned to a specific vehicle. Think of it as the car’s fingerprint. Every VIN encodes key details such as the manufacturer, model, body style, engine type, model year, assembly plant, and a unique serial number.

You’ll find modern 17-character VINs on nearly all passenger vehicles built since 1981. Older vehicles may use shorter formats, which can limit what information is available. For most used-car shoppers today, though, the VIN is the single best identifier for confirming a vehicle’s specs and history.

Where to find the VIN

You can usually locate the VIN in several places. Its most common locations are where the dashboard meets the base of the windshield on the driver’s side (visible from outside), a sticker or plate inside the driver’s door jamb, a stamp directly on the chassis, and official paperwork such as the title, registration, or insurance card.

Always confirm that the VIN matches in all locations — mismatches are a red flag. Another warning: the letters I, O, and Q are never used. If you see these, it’s a sign of fraudulence.

VIN decoder vs. Vehicle History Report

Not all VIN checks do the same thing. There are two main types, and they serve different purposes.

A VIN decoder explains what the VIN means. It can confirm the year, make, model, engine, trim, and sometimes show open safety recalls. This tool helps you verify that the car is being advertised accurately. Decoders also run an algorithm to confirm authenticity.

A vehicle history report goes even deeper. It reveals reported accidents, salvage or flood titles, odometer readings, theft records, and sometimes lien information. This document lets you assess risk before making a purchase.

How to do a VIN check for free

Several reputable sources offer no-cost checks, each with a different focus:

• NICB VINCheck is best for quickly determining whether a vehicle has been reported stolen (and not recovered) or declared a “total-loss” by participating insurers. It’s limited to those flags and caps searches at five per IP address per 24 hours.

• NHTSA Recall VIN Lookup shows manufacturer-reported open safety recalls tied to a VIN, helping you confirm whether critical repairs are still needed. However, it doesn’t include accidents or the title history.

• NHTSA VIN Decoder shares build data such as model year, engine, body type, and restraint systems, but it’s not a history check.

• Commercial sites like VinCheck.info or VinAudit’s free tier aggregate specs and some history indicators from government and industry sources. These services can be useful for spotting obvious issues, but detailed reporting is typically paywalled.

When it’s worth paying for a full report

If you’re seriously considering a used vehicle — especially a private-party sale, a car priced well below market value, or one from a flood- or salvage-prone area — it’s often worth investing in a complete vehicle history. As a rule of thumb, if any free check raises a concern, spending a little on a full report before moving forward is usually money well spent.

Need to find a reputable dealer?

Credit Acceptance has over 15,000 dealers in our nationwide network, many of which are likely to have the vehicle(s) you’re looking for. Use our dealer finder to see those near you, or get pre-qualified for auto financing through our website to receive a shortlist of area dealerships along with the maximum monthly payment you may qualify for.