These days, more and more employers are asking their employees to use their own mobile phone for business purposes (the so-called bring your own device (BYOD) to work concept). The question that arises in this respect is whether or not employers are required to contribute to/reimburse the cost of a personal mobile phone device used for business purposes and how such a contribution/reimbursement is to be taxed.

This BenefitsBit provides the answer to this question from the perspective of Belgium, Luxembourg, Dutch and Swiss employment and tax law.


Although under Belgian law there is no explicit obligation in the legislation or in case law that would oblige the employer to reimburse the cost of a personal mobile phone device used for business purposes, the general thinking is that an employer is indeed required to reimburse expenses incurred when fulfilling the employment contract.

Reimbursement of the cost of using a personal mobile phone will be required if (i) the employee is required to use his phone as part of his professional duties and (ii) he does not have other available means of communication provided by the employer.

The cost of use may be reimbursed on the basis of actual expenses incurred or by a lump sum.

Reimbursement of expenses will not be subject to tax or social security contributions, provided that if a lump sum is paid, it can be demonstrated by a preliminary sample study that the lump sum is reasonable in relation to the actual expenses incurred.


There is no specific legislation or case law in Luxembourg on this issue. However, where an employee uses their personal mobile phone for business purposes, they may ask for a reimbursement of the costs incurred through these business communications, based on the good faith obligation provided for by Article 1134 of the Luxembourg Civil Code.

In the context of an employment agreement, it is considered that this good faith obligation includes a general obligation for the employer to provide the necessary tools to the employee for the performance of their work.

The employee may, therefore, highlight the relevant professional communications in their mobile phone bill and ask their employer to reimburse them. Alternatively, an employer may offer to pay a flat-rate amount to the employee each month to cover a proportion of the costs of the employee’s mobile phone agreement.

The flat-rate solution is the most efficient way to mitigate the tax risk associated with the professional and personal use of a mobile phone by employees.

Indeed, with this solution and provided that the flat rates are reasonable according to the employees’ roles, the employer will not have to prove to the Luxembourg tax authorities that the reimbursed calls were solely professional calls.


There is no specific legislation under employment law which stipulates that the employer is obliged to reimburse the cost of a personal mobile phone device used for work purposes. However, where an employer asks employees to use their own device for work purposes, the employer may be required to contribute/reimburse the cost of the device on the basis of good employer practice (section 7:611 of the Dutch Civil Code).

Under Dutch wage tax law, employers can provide or reimburse the costs of a mobile phone, including data connection costs, on a tax-free basis if the employer considers the use of such a device necessary for the proper fulfillment of the employment contract (i.e. use of the device is mandatory for the employee).


The issue of allocating costs for personal mobile phone devices used for business purposes cannot be answered uniformly, since a distinction has to be made between the costs of the work tools and the expenses incurred in carrying out the work.

In general, the employer provides the employee with the tools and materials that the specific job requires. The parties may, however, provide for an exemption. For mobile phone devices, it may therefore be stipulated that the individual employee can bring in their own device. Where employees provide such tools or materials themselves, e.g. mobile phones, with the employer's consent, they are entitled to appropriate compensation, unless otherwise agreed or as is customary.

The employer must reimburse the employee for all expenses the employee has incurred when carrying out their work. An individual agreement, standard employment contract or collective employment contract may stipulate that such expenses be reimbursed in the form of a fixed sum, such as a monthly allowance, provided that this covers all necessary expenses. Any agreement whereby the employee must bear all or part of these necessary expenses is null and void.

Reimbursement of expenses will not be subject to income tax or social security contributions, provided that the expenses are reasonable in relation to the actual expenses incurred. This may be demonstrated to the tax authorities by a preliminary study. In practice, the Swiss tax authorities generally confirm the (tax-free) lump sum to be paid to the employee within the scope of an expenses manual. Tax-free lump sums confirmed in an expenses manual are therefore the most efficient and common solution for BYOD schemes implemented in Switzerland.