Methodology

Every number on this site comes from the same dataset: 14 collected and verified auction sales of Porsche 964 cars, 9 of them in the valuation bands. The sources so far are Bring a Trailer, with Cars & Bids and PCarMarket and Collecting Cars and Hemmings being added.

What counts as a sale

A completed auction with a stated hammer price. Reserve-not-met cars, withdrawn listings, and asking prices are not sales and never enter the data. If a car sells after the auction ends through the platform, it's recorded with a note saying so.

The bands

Valuations use sales from 2019 on with documented mileage, grouped by model, body, transmission, and mileage band. Cars with substantive modifications are left out of the bands, because a built engine or a turbo swap is a different car at a different price. Cosmetic changes stay in.

What the calculator will and won't do

Three or more sales in a band: you get the median and the observed range. One or two: you get those actual prices, labelled. None: it widens once to the same model and body across transmissions, labels that too, and if there's still nothing it says there isn't enough data. Adjustments for documented items launch unmeasured and stay that way until the data supports a number.

Limits

Auction results skew toward cars people auction. Condition, color, and history move individual cars well off any median, which is why the comps behind every number are linked. This is an estimate built from past sales, not an appraisal.