Both sites offer car values, but values will be slightly different because both sites are using different data sets when assessing value.
CarGurus’ IMV (Instant Market Value) uses an algorithm that considers millions of data points, including the car’s make, model, trim, year, mileage, options, and vehicle history. IMV is an estimated fair retail price for a vehicle based on a detailed analysis of comparable current and previous car listings in the consumer’s market.
Kelley Blue Book (KBB) uses over 250 data sources with 3 trillion data points and then factors in regionalized pricing, market conditions, market trends, the vehicle’s popularity, the condition and facts about the vehicle, economic conditions, and seasonal trends to values.
Which is more accurate is hard to prove; it is up to the consumer to decide which data analysis makes more sense to them.