What is the CarDependability Index (CDi)?
The CarDependability Index (CDi) measures how dependable a vehicle has been, built from real complaints owners file with the National Highway Traffic Safety Administration (NHTSA) and measured relative to how common each vehicle is, so popular models aren’t penalized for sheer numbers. Every covered model year gets two scores — an Early CDi and a Long-Term CDi — rather than a single blended number, and recalls are tracked separately.
What’s the difference between Early CDi and Long-Term CDi?
Early CDi covers a model’s first three years and is graded on a fixed A–F scale with a 0–100 score. Because every model year is measured over the same early stretch, years can be compared fairly. Long-Term CDi reflects complaints across a vehicle’s entire life, shown as a rate per 1,000 and ranked only against other vehicles from the same model year. It doesn’t carry a letter grade, since older model years have simply had more time to accumulate complaints. We never average or blend the two.
Why don’t you rate the two or three newest model years?
Owner feedback takes time to accumulate, and many problems don’t surface until a vehicle has some miles on it. We work strictly with verifiable data rather than early guesses, so our coverage expands automatically as each model year matures.
Are recalls part of the score?
No. Recalls are reported separately and never folded into the grade. Recalls address safety issues, which matter but don’t always reflect everyday reliability, so we show them alongside the scores rather than mixing two different things.
Where does your data come from?
Owner complaints and recall records filed with NHTSA, combined with our own scoring and compilation. The scoring adjusts for how common each vehicle is so the result reflects complaint frequency, not just how many of a model are on the road.
Is the site free to use?
Yes. Our dependability ratings and articles are free to read.
How should I use CDi scores when buying a used car?
As one input, not the whole decision. A specific used car’s condition depends on its history, maintenance, and care. Pair the CDi with a vehicle history report, a thorough test drive, and a pre-purchase inspection from a qualified mechanic.
Can I cite or republish your ratings?
Yes, with credit. You can cite CDi figures for a single vehicle with attribution to “CarDependability Index (CDi).” Citing more than one vehicle also requires a link back to CarDependability.com, and larger uses—more than ten vehicles, or any table or ranking—need our permission. Full details are in our Terms.