Automotive

The tools here use free data from NHTSA, the US National Highway Traffic Safety Administration. Start with the VIN Decoder. Type the 17-character vehicle identification number from the dashboard or door frame, and it shows the make, model, year, engine and factory. It also checks the ninth character, a check digit that catches most typing mistakes.

Next, run the Vehicle Recall Check for the same year, make and model. It lists every safety recall NHTSA has on file, with the problem and the fix. A recall on the model does not tell you whether this exact car was repaired, so ask the seller for records or check the VIN on the NHTSA recalls site. The Car Safety Ratings tool adds the government 5-star crash test scores for frontal, side and rollover tests.

Money and fuel matter too. The Auto Loan Calculator shows the monthly payment and total interest for a car loan. If you compare cars rated in miles per gallon with ones rated in liters per 100 km, the Fuel Efficiency Converter puts them on the same scale. NHTSA data covers vehicles sold in the United States, so cars built for other markets may decode only in part.