The figure a dealer offers for a trade-in almost always sits below the price the same vehicle carries on a forecourt. The gap is not an insult, it is the dealer's costs and risk.
The dealer is buying a problem, not a product
A retail vehicle on a forecourt has been inspected, repaired, valeted, photographed, advertised and warranted. A trade-in has had none of that done to it.
The offer therefore starts from the eventual retail price and subtracts the cost of getting there, plus the margin that makes the transaction worthwhile.
That subtraction is substantial even on a vehicle in good order, because a set of tyres, a service and a full preparation is a real invoice before anything is found.
Unknown faults are priced as risk
The dealer has minutes to assess a vehicle they have never seen, and they will discover its actual condition only after buying it.
Anything that might be wrong is therefore assumed within reason, and the offer includes a margin for what an inspection ramp reveals.
A comprehensive service history and recent invoices reduce that uncertainty directly, which is why documented vehicles genuinely attract better offers rather than merely appearing to.
Holding cost depends on how quickly it will sell
A vehicle the dealer expects to sell in a fortnight is worth more to them than one that will occupy space for months.
Desirability, colour, specification, fuel type and mileage all feed into that estimate, and the offer moves with it even between two identical models.
Where a vehicle does not suit the dealer's usual customers, they will price it to move on to the trade rather than to retail it, which lowers the offer further.
The offer is entangled with the vehicle being bought
Part exchange is rarely negotiated in isolation. A dealer can present a strong trade-in figure alongside a weaker discount, or the reverse, and reach the same total.
This is why the meaningful number is the cost to change, meaning the cash difference between the two vehicles, rather than either figure separately.
Presenting the two as one number also lets a dealer meet an owner's expectation about their vehicle's worth without changing what the deal actually costs.
Selling privately trades money for effort
A private sale captures most of the preparation and margin the dealer would otherwise take, which is why the achievable figure is higher.
The seller absorbs the corresponding work: advertising, viewings, payment security, and the possibility of a dispute after the sale.
The gap narrows on older and cheaper vehicles, where preparation costs form a larger share of value, and widens on newer ones where dealers compete hardest for stock.