How we estimate depreciation

Real market prices

For each model in our list, the value-by-age figures come from actual current used-market listing prices — what a 1-, 2-, 3-, 4- and 5-year-old example is really selling for right now (CarGurus per-model-year average listings, June 2026, cross-checked against Edmunds, KBB, TrueCar and iSeeCars). The "new" price is the typical as-sold price, not a stripped base MSRP. So the dollar figures line up with what you'd see on Carvana or CarGurus, and a Tacoma (a 1-year-old still lists near new) and an Audi A6 (down to the low $50ks after a year) have genuinely different curves — because that's what the market shows.

We interpolate between those annual points and extend past five years with the curve's own late-life slope. For a car not in our list (the "analyze any car" tool), we fall back to a universal front-loaded curve scaled to the segment's average depreciation: value(age) = new price × [1 − depreciation₅ × shape(age)] × mileage factor.

Mileage

A car with more miles than typical for its age is worth less, and fewer miles worth more. We adjust value by about 3% per 10,000 miles above or below the ~12,000‑miles‑per‑year baseline.

Maintenance & the best age to buy

Depreciation alone always favors buying older — the dollars-per-year of value loss are highest when a car is new and keep falling with age. What pushes back the other way is upkeep: repairs and maintenance rise as a car ages. We model that with each model's typical annual maintenance + repair cost (mostly from RepairPal), scaled up with age — roughly 0.6× when new and under warranty, passing 1× around year three and climbing from there.

Putting the two together, the all-in cost per year (depreciation + upkeep) is high when new, drops as you skip the depreciation cliff, then rises again as upkeep takes over — a U-shape with a bottom. We compute that bottom for each car and call it the best age to buy. It is genuinely different per model: a car that holds its value (Tacoma) bottoms out young, while a hard depreciator (a luxury sedan or EV) is cheapest bought several years used, once the steep early loss is behind it.

We only consider buy ages up to about six years. For the worst depreciators the math technically keeps improving with older cars — a cheap, high-mileage luxury car looks great on a depreciation spreadsheet — but repair risk and hassle, which an average-maintenance figure can't capture, make that a gamble. So we cap the recommendation at a sensible used-car window.

Taxes & registration

The cost calculator can add the two costs that scale with what you pay, so they shrink when you buy used: a one-time sales/use tax on the purchase price, and annual registration charged as a percentage of the car's current value (summed over the years you hold it). Both default to U.S. ballparks — about 7% sales tax and a 1%/year value-based registration — and are fully adjustable. Picking your state from the dropdown fills in a typical state-level vehicle tax rate as a starting point; many states add local taxes (often 1–4%) or use special vehicle rules — caps, weight-based excise, a one-time ad-valorem tax, or a rate that differs from the general sales tax — so treat it as an estimate and verify with your DMV. Registration varies just as much (flat rather than value-based in many states); set either to 0 where it doesn't apply. These are estimates to size the decision, not a tax quote.

What's an estimate

New prices, the year-by-year resale figures, and maintenance costs are dated published averages (see the date on each page) and vary by trim, options, condition, mileage, and local market. A few models' intra-year curves are reconstructed where the source data was thin, and the maintenance/age relationship is a model, not a quote. The best-buy-age is the math's answer for an average example — a great deal on a new car or a neglected used one can move it. Always check a specific car's value and history before you buy or sell. Not financial or purchase advice.