Mileage Costs: Calculation and Optimization

Mileage expenses allow for the reimbursement of personal vehicle use for professional purposes. In France, they are calculated using an annual rate published by the tax administration. This rate takes into account the vehicle’s fiscal power (in CV) and the distance traveled. For 2024, a revaluation of +5.4% was applied, with a 20% increase for electric vehicles. In 2025, the rates remain unchanged.

Key points:

• Mileage rate: Flat-rate amounts based on fiscal power and kilometers traveled.
• Electric vehicles: 20% bonus on allowances.
• Manual calculation: Based on specific formulas and rigorous tracking of professional trips.
• Official simulator: Available on Impots.gouv.fr to simplify calculations.
• Digital tools: Solutions like ONexpense automate tracking, reduce errors and integrate official rates.

Properly managing these expenses limits tax errors and optimizes costs for businesses. Adopting digital tools and following current tax rules are essential steps for efficient management.

Legal Framework and Official Calculation Methods

Understanding the Mileage Rate

The mileage rate is the legal basis that governs the reimbursement of travel expenses in France. This flat-rate system, updated annually by decree of the Minister responsible for the Budget, is generally published around March.

Two main elements determine the amount of allowances: the vehicle’s fiscal power (expressed in CV) and the distance traveled for professional purposes over a year. This rate covers several costs related to vehicle use: depreciation, maintenance, fuel and insurance.

A notable feature: electric vehicles benefit from a 20% increase.

Each year, the General Directorate of Public Finances (DGFiP) publishes the official rates, which serve as a reference for calculating declared transport costs. Note that for 2025, these rates have not been increased, unlike 2023 when they were revalued by 5.4%.

Manual Calculation Steps

Manually calculating mileage expenses requires rigorous documentation for each professional trip. Although this method takes time, it remains essential for complying with tax obligations.

The first step is to keep a detailed record of all trips. Each entry must include precise information: date, time, reason for the trip and destination address. This tracking is essential to prove the professional nature of trips in case of tax audit.

The employer must also request a copy of the registration certificate of the vehicle used by the employee. This allows verification of the fiscal power (CV) essential for calculating allowances. An error in this classification could lead to sanctions or adjustments.

Next, you must apply the formula corresponding to the appropriate mileage bracket. For example, for 4,000 kilometers traveled in 2024 with a 5 CV vehicle, the amount of expenses to declare is €2,544 (4,000 km × 0.636).

On the payslip, three elements must appear: the number of kilometers traveled, the rate applied and the total amount of the mileage allowance. This transparency facilitates verification and guarantees optimal traceability of reimbursements.

Using the Government’s Official Simulator

To simplify the process, a digital simulator is available on the Impots.gouv.fr website. This official tool allows mileage allowances to be calculated quickly and reliably, by automatically applying current rates.

The simulator takes into account several parameters: the vehicle’s fiscal power, the annual distance traveled and the type of engine (electric or thermal). It also integrates bonuses for electric vehicles and applies calculations according to different mileage brackets.

One of its major advantages is its automatic update. Any regulatory change is immediately integrated, thus guaranteeing compliance of calculations for businesses and individuals.

The URSSAF website also offers additional information, particularly useful for employers who must include these allowances in their payroll management.

« Although the Administration is not authorized to interfere in business management, it can however, in accordance with consistent jurisprudence of the Council of State, challenge expenses that would not relate to normal management or would not have been incurred in the direct interest of the company. »

This statement from the Ministry of Economy and Finance highlights the importance of rigorous and justified management of mileage expenses. By using official tools like the government simulator, businesses and individuals strengthen the legitimacy of their calculations and protect themselves in case of tax audit.

Mileage allowances (IK): the ULTIMATE guide

Digital Tools for Mileage Expense Management

After exploring manual and official methods, let’s look at digital solutions that simplify and streamline mileage expense management.

ONexpense Features for Mileage Tracking

ONexpense offers an intuitive solution for French SMEs and VSEs, making mileage expense management more fluid through its automated tools. By integrating official mileage rates, the platform guarantees constant tax compliance.

The mobile application, compatible with iOS and Android, offers automatic trip tracking. It detects and records each professional trip in real time thanks to geolocation and timestamping. Result: complete traceability, essential in case of tax audit.

With its OCR technology, ONexpense instantly analyzes supporting documents such as toll tickets or fuel invoices, then archives them for a regulatory period of six years. This data is then used to calculate mileage allowances taking into account the vehicle’s fiscal power.

Another asset: integration with French accounting software such as SAGE or Quadratus, facilitating direct data export to payroll systems.

Benefits of Automation

Automating mileage expenses allows companies to save valuable time. For example, manually processing an expense report takes about 20 minutes, plus 18 minutes to correct any errors. With ONexpense, this process is significantly shortened.

Moreover, 19% of expense reports contain errors. By relying on automatic calculations based on official rates and rigorous verification, ONexpense significantly reduces these risks.

For professionals like sales representatives or consultants, who make numerous daily trips, automated tracking ensures that no kilometer is forgotten. According to studies, this approach improves internal compliance.

ONexpense also integrates powerful anti-fraud controls. These detect anomalies such as inconsistent trips or duplicates. Users receive automatic notifications to validate their trips and submit their expense reports on time, which improves their cash flow management.

Finally, secure and timestamped archiving complies with the requirements of the French General Tax Code, offering peace of mind in case of audit.

« It’s at least 90 to 95% less work for us now thanks to card integration, compared to the previous process with paper and Excel » – Gerald Evers, CFO at Lucien Bikes.

Thanks to this automation, ONexpense frees businesses from administrative constraints, allowing them to devote more resources to their main activity. These tools integrate perfectly into a strategy aimed at simplifying and optimizing mileage expense management.

Cost Optimization Strategies

Efficiently managing mileage expenses requires much more than a simple calculation. Companies that succeed in reducing their transport costs adopt thoughtful methods and rely on powerful digital tools. Here are concrete approaches to optimize these expenses.

Choosing the Most Suitable Deduction Method

Choosing the deduction method is a key step in controlling your expenses. This involves deciding between mileage allowance and actual expenses.

• Mileage allowance: Based on the official rate, it calculates the deductible amount according to distance traveled and the vehicle’s fiscal power.
• Actual expenses: Allows deduction of real expenses, such as fuel, maintenance, insurance or depreciation.

The decision depends on the vehicle’s characteristics and costs incurred. For example, if the vehicle is recorded as a company asset, the mileage allowance is not applicable. In this case, actual expenses become mandatory according to current rules.

Route Optimization and Expense Auditing

Reducing unnecessary kilometers can generate substantial savings. Route planning software, for example, can reduce transport costs by 10 to 20%. These tools optimize not only routes, but also fuel consumption and delivery times.

Real-time GPS systems offer another dimension of efficiency. They allow immediate route adjustments, limit unnecessary stops and ensure punctual deliveries. In parallel, conducting regular audits of expense reports ensures compliance with internal policies and tax regulations. A striking fact: 54% of VAT is not recovered each year, which underlines the importance of rigorous monitoring.

ONexpense: Precise Digital Tracking

Once deduction methods and routes are optimized, tools like ONexpense complement the approach by offering detailed and structured tracking. This platform offers advanced features to analyze travel habits by employee or department. Result: spending trends are quickly identified and improvement areas become evident.

ONexpense also automates compliance with internal policies, by detecting non-compliant requests. Reimbursements are accelerated and administrative errors reduced. Thanks to real-time notifications and a mobile interface, expense management becomes proactive and accessible.

For electric vehicles, ONexpense automatically applies the 20% increase provided by regulation. This optimizes reimbursements while encouraging more environmentally friendly practices.

A Broader Vision: Towards Sustainable Alternatives

Some companies adopt initiatives that go beyond simple transport costs. For example:

• Air Liquide: Subsidizes the purchase of bicycles (classic and electric) and offers a sustainable mobility package to encourage cycling.
• TotalEnergies: Supports the acquisition of electric and hybrid vehicles for its employees, while installing charging stations on its sites.

By combining thoughtful methodology, powerful technological tools and forward-looking company policies, mileage expense management becomes a real asset for improving company competitiveness.

Key Takeaways

Mileage expense management is based on three fundamental elements: precise calculation, compliance with tax rules and the use of digital tools. These aspects, addressed in the previous sections, form a solid foundation for optimizing business travel management.

Respecting tax regulations is essential. This is not limited to avoiding sanctions or tax adjustments, but also allows maximizing possible savings. Imprecise management can lead to costly errors for the company.

Process automation is a real performance lever. Companies that adopt digital solutions for mileage expense tracking not only save time, but also reduce the risk of human error. In addition, these tools offer real-time visibility on expenses, a valuable asset for efficient financial management.

« It’s at least 90 to 95% less work for us now thanks to card integration, compared to the previous process with paper and Excel » – Gerald Evers, CFO at Lucien Bikes.

Thanks to digitization, reimbursements are accelerated, administrative tasks lightened, and companies gain transparency on their expenses.

Looking to the future, complete integration of digital tools in mileage expense management seems inevitable. This approach promises even smoother processes and increasingly clear and efficient management.