It’s one of the most repeated pieces of car-buying folklore: “The moment your tires cross the curb leaving the dealership, your brand new car evaporates 20% of its value.”
Financial advisors repeat it, parents warn their kids about it, and used-car salespeople may use it to frame a purchase. It sounds logical, but in a constrained inventory market, is that 20% number still sound?
The short answer: False.
The Origin of the Number
Decoding the myth requires understanding the gap between "Trade-In Value" and "Retail Value." Decades ago, if you bought a $40,000 sedan, drove it across the street, and immediately sold it back to a different dealer, they would offer you $32,000. People interpreted that $8,000 drop as instantaneous market depreciation.
In reality, the car didn't lose its innate market value. You simply shifted your position from being a Retail Buyer to a Wholesale Supplier. The dealer was quoting you the wholesale rock-bottom price necessary to leave sufficient margin for them to clean, remarket, and re-sell that car back to the public at $39,000.
How current demand changes the math
On highly desirable models, the 20% rule does not describe every transaction. Production shortages and supply changes have affected resale values. If you purchase a high-demand vehicle such as a Toyota Tacoma, Honda Civic, or Ford Maverick, the first loss may be smaller than the old rule suggests.
When a used car is not cheaper
If you assume a new car loses 20% immediately, you may choose a 2- or 3-year-old used car without comparing the full cost. As we explain in our near-new car guide, a used vehicle may sell near the price of a new one while carrying a higher interest rate.
The bigger risk is overpaying for a used car because you believed the 20% rule.
Compare the numbers
Depreciation depends on the exact vehicle, mileage, condition, incentives, and current wholesale and retail prices.
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