Sharing the costs of a car trip between the driver and passengers seems simple on paper. But between the price of fuel, tolls, service fees from platforms, and tax regulations, the final amount varies considerably depending on the calculation method used. How much does carpooling really cost, and above all, how can one ensure that the set rate remains within the tax administration’s guidelines?
Carpooling: actual cost sharing vs. mileage rate
Two methods coexist for setting the price of a carpooling seat, and they do not yield the same result at all.
The first involves adding the cost of fuel and the amount of tolls, then dividing the total by the number of occupants, including the driver. This is the method of actual costs, the most common on platforms.
The second relies on the official mileage rate, which includes vehicle depreciation, insurance, and maintenance. The ceiling accepted by the tax authorities is therefore significantly higher than the simple fuel-toll sharing. A detail that can be found by consulting carpooling costs on Autoscope, which details these two pricing logics.
In practice, most drivers set their rates well below the mileage rate. The choice of method mainly depends on the goal: to strictly cover immediate expenses or to include a portion for vehicle wear in the sharing.
Tax threshold for carpooling: when cost sharing becomes taxable
The transport code defines carpooling as a trip made “on a non-remunerated basis, except for cost sharing.” The tax doctrine published in the BOFiP specifies that the amounts received are not taxable as long as they remain within the limit of cost sharing.
Three conditions must be met for carpooling income to be exempt from tax:
- The trip must have been initially planned by the driver for their own account, not organized solely for the purpose of transporting passengers
- The driver counts themselves in the sharing (if there are 4 in the car, divide by 4, not by 3)
- The amount charged per passenger does not exceed the share of actual costs or, at most, the ceiling of the mileage rate divided by the number of occupants
Above the ceiling, the entire amount received becomes taxable, not just the excess. The risk is therefore not negligible for a driver who sets their prices too high on several regular trips.
Commuting trips: particular vigilance required
For daily carpools, the repetition of trips generates an annual accumulation that can attract the attention of the tax authorities. A driver who transports two passengers every day on a medium-distance trip accumulates significant sums over a full year.
Only the driver’s personal share remains deductible from actual costs in their income tax return. The share reimbursed by passengers cannot be counted as a deduction, which mechanically reduces the tax advantage of declaring actual costs for regular carpoolers.
Daily carpooling costs: little-known aids and reductions
The price displayed on a platform does not always reflect the final cost borne by the passenger or the driver. Several mechanisms come into play to modify the equation.
The sustainable mobility allowance, when implemented by the employer, can cover part of the carpooling costs for the commuting trip. This scheme applies to both the driver and the passenger. It is not automatic: the employer decides to offer it and sets the amount within the legal ceiling.
Some local authorities provide direct incentives, sometimes to the driver, sometimes to the passenger, or even to both. These aids can make certain trips free for the passenger. The common condition: booking through a platform partnered with the local authority, which excludes informal arrangements.
Platform service fees: a cost to factor in
Carpooling platforms charge service fees on each booking. This amount is added to the price set by the driver and can represent a significant portion of the total fare paid by the passenger.
- The driver receives the price they set, with no direct deduction from their share in most cases
- The passenger pays the displayed price plus the platform’s service fees
- Cancellation conditions vary from one platform to another, sometimes with fees retained in case of late cancellation
- Comparing the total cost (fare + service fees) between platforms gives a more accurate picture than just the trip price
Reading the cancellation conditions before booking allows for assessing the real cost of a trip, not just the displayed fare. A trip canceled at the last minute can cost more than a train ticket if the fees are non-refundable.
Calculating the carpooling fare: the method for setting a fair price
For a driver who wants to set their price without tax risk, the simplest calculation remains that of actual costs. One adds the cost of fuel for the trip (average vehicle consumption multiplied by the price per liter, over the distance traveled) and the amount of tolls. This total is then divided by the number of occupants, including the driver.
This method produces a defensible rate in case of a tax audit and is perceived as fair by passengers. The driver does not earn anything; they simply reduce their travel costs.
The mileage rate remains a ceiling accepted by the administration, not a recommended rate. Systematically setting prices at the level of the mileage rate would expose one to questions about the truly non-commercial nature of the activity, especially for regular trips.
Carpooling operates on a simple but regulated principle: the driver shares their costs, no more. Whether the trip is occasional or daily, it is this ceiling that separates lawful cost sharing from taxable income. The variable that changes everything is the number of passengers on board, as each additional occupant lowers each person’s share and moves away from the tax threshold.
