How to calculate vehicle depreciation for reimbursement
Understand how vehicle depreciation affects mileage reimbursement rates.
Why depreciation is the most ignored part of reimbursement
When companies set mileage reimbursement rates, the instinct is to look only at fuel. It is the most visible cost, it shows up at the pump, and everyone feels it in their wallet. But fuel usually represents less than half the real cost of driving a mile. Depreciation — the silent loss of vehicle value with every mile traveled — is often the most expensive line item and, at the same time, the one most easily forgotten when calculating a fair rate.
Ignoring depreciation means the employee is, in practice, financing part of the company's operation with their own asset. Their car is worth less after every business trip, and that needs to be compensated. A mature policy recognizes depreciation as a legitimate cost and bakes it into the per-mile rate.
How vehicles lose value over time
Vehicles lose value over time and with use.[^rfb-in1700] On average, a new car loses between 15% and 20% of its value in the first year and then roughly 10% to 15% annually thereafter. This curve is not linear: the steepest drop happens early in the vehicle's life and slows as the years pass.
Accumulated mileage accelerates that loss. Two identical cars of the same age can have very different resale values if one drove 9,000 miles a year and the other 25,000. That is exactly why heavy work use deserves proportional compensation.
The practical per-mile depreciation calculation
To arrive at per-mile depreciation, divide the expected annual loss in value by the number of miles you plan to drive in a year. A clear example: a US$ 30,000 car with estimated depreciation of US$ 4,500 per year, driven 12,000 miles annually, works out to about US$ 0.375 per mile in depreciation alone.
That figure on its own shows why rates set too low are unfair. Before paying a cent for fuel, maintenance, or insurance, the employee has already consumed real value in the vehicle for every mile driven.
Adding up all costs for the total rate
Depreciation is only one part of the equation. To reach the total reimbursement rate, also add fuel, preventive and corrective maintenance, tires, insurance, registration, and taxes. Each of these behaves differently: fuel tracks gas prices, maintenance rises as the car ages, and insurance depends on the driver's profile.
Serious companies model all these factors together. The final rate should reflect the real cost of owning and operating the vehicle, not an arbitrary number copied from another company or a stale table. The US IRS standard mileage rate exists precisely to bundle these elements into a single defensible figure.
Why annual rate review matters
Conduct an annual rate review, adjusting according to the fleet's average age and current market costs. Fuel, parts, and insurance change in price every year, and a frozen rate quickly falls out of date.
Outdated rates hurt both sides. Set too high, the company overpays. Set too low, the employee absorbs the difference and feels penalized for using their own car for work. A yearly check keeps the rate honest for everyone.
Documentation and audit support for the calculation
Keeping a documented calculation memo protects the company in case of an audit and gives the employee transparency. Record the assumptions you used: the vehicle's reference value, the depreciation percentage adopted, the average annual mileage, and the full breakdown of the rate.
This documentation also makes internal audits easier and answers questions from HR or finance without improvisation. When every cent of the rate has a clear origin, disagreements become technical conversations rather than disputes.
How Quilometragem helps with control
Calculating the correct rate is the first step; applying it consistently is the second. Quilometragem records every trip with date, origin, destination, and distance, generating standardized receipts that automatically apply the rate defined in your policy.
With a digital history, it is simple to track each employee's accumulated mileage, revisit depreciation assumptions, and export the data to Clara when processing payments. That way the theory of a fair calculation becomes daily practice, with no lost spreadsheets and no figures redone from scratch every month.
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