Car Depreciation Calculator

Why Depreciation Is the Biggest Cost of Owning a Car

For most cars depreciation is the largest single cost of ownership, ahead of fuel, insurance and servicing, and it is the only one that never sends a bill. It is collected once, at the moment of sale, for value that drained away over years.

The scale is easy to see at the default figures. A 25,000 car depreciating 15% a year is worth 11,092.63 after five years, so 13,907.37 has gone, which is 55.6% of the purchase price and an average of 2,781.47 a year.

That average is the figure to treat with most caution, because the loss is not spread evenly. Applying the same 15% rate, the first year costs 3,750 and the fifth costs 1,957.52. The rate is constant; the amount it removes falls every year, because it is applied to a smaller number each time.

How Depreciation Actually Behaves

Real depreciation is steeper still at the front. The drop from new to used happens the first time the vehicle changes hands, before any wear has occurred, and a single constant rate cannot represent it. A pattern of 20% in year one followed by 15% thereafter leaves 10,440.12 after five years rather than 11,092.63, so a flat rate overstates the remaining value by about 6% on this example.

Two adjustments handle that. Entering a higher rate raises the whole curve and approximates the early cliff at the cost of overstating later years. Starting from a used purchase price avoids the cliff entirely, because most of it has already been taken by the previous owner, which is the arithmetic behind buying used.

The calculator applies one rate compounding on the remaining value, which is the declining-balance method used in accounting for assets that lose value fastest when new. It gives a clean approximation from year two onward and understates the first year for a car bought new.

Depreciation is also the reason a car is an unusual purchase to finance. The asset falls in value on a curve while the loan falls on a schedule, and for the first part of the term the second can lag the first, which is what leaves an owner holding a vehicle worth less than the balance outstanding.

Common Things People Overlook

Three things move the rate more than anything the calculator can see. Model reputation is the first: vehicles with a track record for reliability and steady demand hold value better, and the gap between the strongest and weakest performers in the same segment is wide enough to change the answer materially. Mileage is the second, and it works in the opposite direction from intuition: a high-mileage used car depreciates more gently in percentage terms because most of the fall has already happened.

Model cycles are the third. A car in the final year before a redesign loses value faster because it becomes the outgoing version the moment its replacement is announced, which is a timing effect rather than anything about the vehicle itself. Fuel type belongs in the same category, since shifts in technology and policy can reprice whole segments of the used market faster than any wear-related curve would suggest, a shift the International Energy Agency tracks across regions.

Local resale data is what settles any of this. Rates differ by market, by segment and by year, so a figure drawn from actual listings for the same model at the current age and a year older beats any published average.

A worked example

With a purchase price of 25,000, an annual depreciation rate of 15% and five years, the tool returns 11,092.63 remaining. The supporting rows show 13,907.37 of value lost, 55.63% of the original price, and an average loss of 2,781.47 a year. Default purchase prices adjust to the selected currency, so the figures here follow the base setting.

What moves the number most

The rate is the input that dominates, and it dominates non-linearly because it compounds. At 10% the same car keeps 14,762 after five years; at 20% it keeps 8,192. Three percentage points either side of the default move the remaining value by roughly two thousand in each direction.

The time horizon behaves the same way. Each additional year removes 15% of what is left rather than 15% of the original, so the marginal loss shrinks: year six costs 1,663.89 against year one's 3,750.

Purchase price is the only input that scales the result proportionally. Doubling it doubles both the remaining value and the loss, leaving every percentage unchanged, which is why the rate and the horizon are the two worth getting right.

The formula behind this

Remaining value is the purchase price multiplied by one minus the annual rate, raised to the power of the years held. Value lost is the purchase price minus that remaining value, and the average annual loss divides the total loss by the years.

Because the rate applies to the reducing balance rather than to the original price, the value never reaches zero in the model however long the horizon runs. That is a limitation at long horizons, where a real vehicle eventually reaches a scrap or floor value that a declining-balance curve approaches but never touches.

Reading the figure against the alternatives

A depreciation figure only becomes useful when it sits next to something. On its own, 13,907 of lost value over five years is a number; against the fuel, insurance, servicing and tax paid across the same period it is usually the largest line, and against the alternatives to owning a car at all it is the one that makes the comparison honest.

It also reframes the purchase itself. The relevant question at the point of buying is not what the car costs but what fraction of that cost will still exist at the point of selling, and the curve here answers it directly: at 15% a year, roughly 44% of the price survives five years and 27% survives eight.