When it's time to move a car on, you've really got two choices: hand it to the dealer as part of the deal on your next one, or sell it yourself to a private buyer. Part-exchange is the easy door: drive in with the old car, drive out in the new one, one set of paperwork. Selling privately is the profitable door, but it asks for your time, a bit of nerve and a fortnight of your phone buzzing. The right answer isn't the same for everyone, and it comes down to what the gap between the two figures actually is.
Why part-exchange always pays less
A dealer taking your car in part-exchange has to make money on it. They'll recondition it, warranty it, park it on the forecourt tying up cash until it sells, and carry the risk of anything they discover once it's theirs. All of that comes out of the figure they offer you. As a rule of thumb the part-ex price sits a few hundred to a couple of thousand pounds below what a private buyer would pay for the same car; more on a desirable model, less on something slow to shift.
What you get in return is genuinely valuable, though, and it's worth naming honestly rather than pretending part-ex is a rip-off:
- It's instant. The old car is gone the day the new one arrives. No overlap, no two insurance policies, no car sitting on the drive waiting for a buyer.
- It's safe. No strangers at your house, no test drives with someone you've never met, no cash or transfer to verify.
- It can settle finance for you. Owe money on the car? The dealer can clear the outstanding balance and fold it into the new deal, which is far tidier than doing it yourself.
- It can save a little tax if you're a business, and it simplifies the whole transaction into one contract.
What selling privately really involves
Sell it yourself and you keep the margin the dealer would have taken, but you do the dealer's job. That means writing an honest advert with good photos, answering messages (including the time-wasters and the lowballers), arranging viewings, sitting in the passenger seat on test drives, and handling the money safely at the end. None of it is hard, but it's real effort spread over days or weeks, and it only makes sense if the extra money justifies the hassle for you.
A few things make the private route smoother and safer. Price it by checking what similar cars (same age, mileage and spec) are actually advertised for, not what you wish it was worth. Take the payment as a bank transfer you've seen clear, or cash you're confident in, before the buyer drives off. And be ready for buyers to check the car properly: the savvy ones will run a free MOT check and a full history report before they commit, so a clean, verifiable record actually helps you sell faster and defend your price.
The maths that decides it
Strip away the emotion and it's a simple sum. Get a couple of part-exchange figures: dealers will value your car as part of a deal, and the online "we buy any car" services give you a quick floor price. Then work out a realistic private selling price from the live adverts. The difference between those two numbers is what selling privately is worth to you.
If that gap is £300 on a £4,000 car, most people take the easy part-ex and never think about it again. If it's £1,500 on the same car, that's a fortnight's effort paying you the equivalent of a very good hourly rate, and it's hard to justify giving it away. There's no universal answer, only your figures and how much you value your own time and hassle.
A word on cars with finance
If there's still finance on the car, it changes both routes. You can't sell a financed car privately with a clear title until the agreement is settled, and you can't simply hand it over in part-exchange without dealing with the balance either. Get a settlement figure from your lender first. If the car's worth more than you owe, that equity is yours whichever way you go; if you owe more than it's worth, that negative equity has to be paid off or rolled into the next deal. Knowing the number before you negotiate stops a dealer burying it in the paperwork, the same principle covered in our outstanding finance guide.
The honest recommendation
If you value your time and just want the whole thing done, part-exchange is a perfectly sensible choice and there's no shame in taking it. If you're comfortable spending a couple of weekends on it and the private price beats the part-ex by a meaningful margin, selling privately puts real money back in your pocket. Get both numbers before you decide anything. If you do go private, a clean history report to show serious buyers makes the car easier to sell and the price easier to hold.