The numbers · a guide
How to tell if a used car is fairly priced
Here’s the uncomfortable part: the seller has priced dozens of cars. You’ll price a handful in your life. The asking price is their opening move in a game they play daily and you play twice a decade — which is why “it seems about right” is the most expensive sentence in used-car buying.
The drift is measurable. We price every live UK advert against a fitted fair-value curve, and right now 1 in 14cars on sale is asking above its fair range. Those cars sell too — to buyers who didn’t check.
The method below is what “checking” actually means. You can do all of it by hand in half an hour; at the end we’ll admit that we’ve automated it.
1. A fair price is a range, not a number
Two identical-spec cars can honestly differ by hundreds of pounds — condition, colour, timing, the seller’s patience. So the question is never “is £9,200 correct?” but “what band do cars like this actually occupy, and where in it does this one sit?” A car in the band is fairly priced. A car above it needs a reason you can inspect — and “one lady owner” is not worth £1,400.
2. Build real comparables — same car, not similar cars
The classic mistake is comparing against three adverts. Three adverts is an anecdote. You want every live example of the same model, same year, similar mileage — a Golf is not a comparable for a Polo, and a 2018 with 30,000 miles is not a comparable for a 2018 with 90,000. Search the big marketplaces with tight filters, note every asking price, and find the middle. Twenty comparables make a market; three make a story.
Beware the survivor trap: adverts you can see are the cars that haven’t sold. The well-priced ones disappear in days, so a snapshot of listings skews expensive — one more reason the middle of the band, not the bottom of it, is your reference.
3. Adjust for mileage — it’s worth more than you think
Mileage moves value continuously, not in cliffs. On a mainstream car, the difference between 40,000 and 80,000 miles is commonly £1,000–£2,500 of value — so a car that looks cheap against its year-mates often just has more miles on it, priced in. When you compare, compare at the same mileage or mentally slide the price along the curve. Every model page on this site draws that curve from live adverts, with a table of fair values by year and mileage — that’s the adjustment done for you.
4. Negotiate from the band, not from the ask
Once you know the band, the conversation changes shape. Not “will you take £8,500?” — plucked from politeness — but “comparable cars are making £8,300–£8,900 and this one’s up at £9,600; what’s the £700 for?” Sometimes there is an answer (new clutch, full history, warranty). Often there isn’t, and a seller who knows their price is above the market expects this conversation. The buyer with numbers is the buyer who gets movement.
The admission: we automated this
Everything above is real and you can do it by hand. It’s also exactly what this site does in ten seconds: paste any listing and it’s placed on a curve fitted to 359,216 live adverts — the band, the position, the verdict, free. The same arithmetic also ranks today’s furthest-under-the-band cars, and before you commit to any of them, check the car itself — a fair price on a written-off car is not a fair price.
Got a listing open in another tab?
Ten seconds, no account, and you’ll know which side of fair it sits on.