How the Lemon Index works

1. Complaints: the full NHTSA owner-complaint file (1,607,537 vehicle complaints, 1995 to October 2026).
2. Sales: U.S. sales per model per year from automakers' published figures. Tesla doesn't report by model, so we use published estimates and say so.
3. Same window for every car: a complaint counts only if it was filed within 3 years of the model year.
4. Rate: complaints per 100,000 cars sold, matched model year to sales year.
5. Index: each car's rate against the average car of the same model years. 100 = average, 50 = half the complaints, 300 = triple.

What it doesn't measure

A complaint is a safety complaint filed with the government, not a repair record. Fleet and rental-heavy models have fewer owners filing. Luxury lessees often go straight to the dealer. Some owners file more readily than others. Read it as early-life safety complaints, not total cost of ownership.

Using the data

The rankings are free to cite with a link to lemonindex.com (CC BY 4.0). The raw complaint data is public at NHTSA.