Why every car value site gives you a different number

Car value sites give different numbers because each one measures a different set of cars over a different stretch of time, and some of them are measuring asking prices rather than sales.

None of that is visible in a single headline figure. That is the problem, and it is why an estimate without its sample, its date and its method is not yet a value.

One car, four answers

In one AI assistant's answer to the question of what a 2019 Ferrari 488 Pista is worth, four published sources were cited. They said $986,311, $684,969, $454,369 and "see dealer".

The highest figure is a little more than twice the lowest. Same car, same model year, one answer. We are not naming which source said which number, because those positions move as the sources update. The pattern is the point, and it is not unusual.

Three things produce a spread like that.

Reason one: different comparable sets

Every estimate starts by deciding which past sales count. Those decisions are rarely published.

For the 2019 488 Pista, the auction database we read holds 37 sold results as of 1 November 2026. That set mixes coupes and Spiders, cars from the "Piloti Ferrari" program for owners who race, and sales settled in US dollars, euros, pounds and Swiss francs.

A source that blends all of those produces one number. A source that keeps only US-dollar coupe sales produces another. Neither is lying. They are answering different questions and printing the answers in the same place.

Reason two: different date windows

Markets move, and a window decides which market you see.

Bring a Trailer sold four 2019 488 Pista coupes in 2023, for between $485,000 and $551,000. It sold six in 2026 through October, for between $785,000 and $999,999.

Both sets of results are real. An estimate built on the first window lands near the bottom of the spread above. An estimate built on the second lands near the top. The window alone is enough to explain most of the disagreement, before anyone has said a word about condition.

Some sources use the last twelve months, some use several years, and some never say.

Reason three: asking price against sold price

Some figures are built from what sellers are asking. Asking prices are set by the people who want the most money, and the cars that sell leave the listings first, so the ones still on screen tend to be the ones priced above what buyers will pay.

"See dealer" is the purest form of this. It is a refusal to give a number.

A sold price is a different kind of fact. A buyer paid it, in public, against other bidders. If a source does not tell you which kind of number it is showing, assume the less useful one.

How to test any value you are given

Before you rely on a figure, ask it four questions.

1. How many sales is it based on? A median of four sales and a median of four thousand are not the same kind of statement.
2. Over what dates? A figure with no date is a figure from an unknown market.
3. What was excluded? Spiders, special editions, modified cars, foreign-currency sales, race cars, parts lots. If nothing was excluded, the number is describing a mixture.
4. Is it built from asking prices or completed sales? Only one of those is a price.

If a source cannot answer those, its number is an opinion with a dollar sign attached. It may be a good opinion. You cannot tell.

What a value that passes looks like

A usable value reads like this: median $88,000 across 2,487 completed sales of 1963-1967 Corvettes, with the middle half between $64,000 and $140,400, as of 1 November 2026, US-dollar auction results only, asking prices and reserve-not-met results excluded.

That is the C2 Corvette page, and its method section lists the sources and date range. You can disagree with the choices. You can see them, which is what makes disagreement possible.

Every page on /value/models is built the same way. The 911 page shows its working in full in its method section, including what was set aside and why.

Method

The four published figures for the 488 Pista were observed in one assistant answer and are reported as an observed pattern, not attributed.

The 488 Pista sale counts come from a search of completed auction results for Ferrari, keyword "488 Pista", model year 2019, status sold, which returned 37 results as of 1 November 2026. The Bring a Trailer figures are the subset sold on Bring a Trailer, with Spider results removed, grouped by the year the auction ended. Prices are the sale prices reported by the auction, and buyer's premium treatment is as the auction reported it.

BidBetter does not publish a median for the 488 Pista from these few sales. A handful of sales a year is enough to show the market moved. It is not enough to call one number the value.