How CarHawk prices a car

CarHawk reads the newest private-seller listings on each platform on a fixed cycle: Facebook Marketplace every 3 minutes, Gumtree every 5 minutes, and Carsales continuously. A car listed on more than one site is recognised and alerted once.

Market value is the median asking price of comparable cars currently advertised across all three platforms. A comparable is the same make, model and badge, a model year within one either side, and close in kilometres: CarHawk keeps the closest matches, counting a year's difference as 15,000 km.

Private-seller asking prices are preferred. When there are not enough, dealer prices are used and brought down to private-sale terms first. Same-year cars carry more weight than the year either side.

A damaged car advertised cheaply would drag the median down and make every clean car look like a bargain. So listings that describe a problem are left out of the comparables:

Those cars can still reach you as alerts, with the problem flagged on the card. Wanted ads, swaps and parts-only listings are ignored altogether.

Each comparable is adjusted to the kilometres of the car being priced, by about 0.18% of its price per 1,000 km of difference. A lower-kilometre car can gain at most 15%; a high-kilometre car can lose up to 60%. Where a comparable has no odometer reading, CarHawk assumes 15,000 km a year.

Sellers drop a zero, add one, or write the kilometres in thousands. CarHawk compares the odometer with the car's age and, when a correction is clearly more believable, prices the car at the corrected figure and says so on the alert.

Wholesale is roughly what a trader would pay: market value less a gap, which is the greater of $1,500 or 20%, capped at $8,000. A car is a deal when its asking price is at or below wholesale less the same gap again, calculated on wholesale. That second gap is your margin for repairs, costs and profit.

After an alert, Evaluate deal costs the repairs and checks the car still returns 20% after them. Here is the rule on the 2019 Toyota HiLux SR5 from the app:

Comparables come from cars seen in the last 14 days, and every live listing is re-read each week, so cars that have sold drop out and price changes are picked up. Market value follows the market as it moves, rather than a book figure printed months ago.

• It does not inspect the car. Values and repair costs are estimates from the ad, the photos and other listings.
• It does not contact sellers or buy cars for you. You deal with the seller directly.
• It cannot promise every listing is found, or that a car is still for sale when you call.
• It does not alert on dealer listings. Alerts are for private sellers.
• It is not financial advice, an appraisal or a roadworthy. Inspect every car and check its history before you buy.