Article: According to the Internal Revenue Service, a FMV is an estimate of the sales amount that a private seller and buyer would agree to for a vehicle. In contrast, a trade-in value is what a dealership would offer. It's also important to note that the FMV is calculated based on the actions of willing buyers/sellers, not ones under duress. Trade-in values for used cars are also often altered by dealers to boost vehicle sales. An FMV estimate is more consistent. If you are looking up an estimate for someone else or if you are researching an older vehicle, you may not know every detail requested by the website. That's okay. Enter in a number of years or a series of options to create a workable value range. For example, if you know that the car was made in the late 1990s, enter in 1996, 1997, 1998, and, 1999. Note how the values differ with each year. Look at the automobile listings in your local newspaper. Or, go to a used auto sales website such as www.autotrader.com, enter in your zipcode, and search for similar cars in your area. Make note of the asking prices for cars that are similar to your own. For example, if you are selling a 1999 Mustang and see a 2000 model in your local paper, note the price. It's probably a bit higher than your car's FMV, but may be pretty close to it.

What is a summary?
Recognize that FMV is different than trade-in value. Enter in reasonable comparison details if you don't know the exact information. Compare your car to others currently for sale.