AutoTrader is an online marketplace for consumers and dealers to find potential buyers and advertise vehicles for sale. They are one of the largest and have been established since 1977 when they launched their weekly automotive classifieds magazine. They began their online presence in 1995 with their website allowing people to buy and sell their vehicles over the internet. This has allowed them to collect a lot of data about the asking price of cars advertised on their platform. Because they don't actually sell the cars themselves, they have no visibility on the actual final sale price.
You can get an AutoTrader car value for free, it is available on their website under their AutoTrader Car Valuation section. They merely require a reg number and your current mileage. The AutoTrader valuation will give you a guide as to what they think your car would sell for privately and what you could expect as a part exchange price. They assume your vehicle is in 'good' condition and don't take into account any extras you may have on the car. Often the AutoTrader car valuation can be higher than other sites because they only know the asking prices. In reality, the final selling price is usually less than the asking price. AutoTrader also has a vested interest in leading you to think your car's value is more to try and gain your business and to get you to pay for an advert on their platform.
It's true that selling privately you are likely to achieve the best price, but you also expose yourself to timewasters, tyre-kickers, and potentially even fraudsters. So it's not for everyone!
Remember that like all valuations; an AutoTrader car valuation is only an estimate. Because their data is based on the asking prices from their platform and not the final sold price, you should take this into consideration. There are lots of other factors that can influence what your car is worth. Such as market conditions, how much demand there is, how common your vehicle is will all affect its value too.
Free valuation tools available.