Voluntary overtime hours are popular with employers because they allow them to have their employees perform overtime without any justification ground being required. Whilst the system was rather complex in the past, with two different types of voluntary overtime hours applying — namely "ordinary" voluntary overtime hours and the so-called "relance" overtime hours — it has now been simplified to include just one type of voluntary overtime. Moreover, the number of voluntary overtime hours that can be performed has been increased from 240 hours to 360 hours per calendar year. Of these, 240 hours are exempt from social security contributions and taxes and are therefore paid on a net basis. The Act was published in the Belgian State Gazette on 1 June 2026, but the new rules retroactively entered into force on 1 April 2026.
What are voluntary overtime hours?
Unlike "normal" overtime hours, which can only be performed on the basis of a limited number of specific grounds (e.g. an unexpected increase in workload, work to prevent or repair damage to assets, etc.), voluntary overtime hours can be used without any need for justification.
However, to perform such voluntary overtime hours, the employee's prior written consent will be required. In other words, the employer cannot introduce the system unilaterally.
Remember the "old" rules? A look back before the reform
Before the reform, there were two types of voluntary overtime hours:
- "Ordinary" voluntary overtime hours that could be performed up to 120 hours per employee per year (or a higher number determined by a sector-level Collective Bargaining Agreement). These hours were "expensive" as they were subject to overtime pay, social security contributions and taxes. However, no compensatory rest needed to be granted.
- "Relance" voluntary overtime hours, which were introduced during Covid for a fixed period and have since then always been extended. Relance voluntary overtime hours were more advantageous as they were exempt from social security contributions and taxes (gross = net) and no overtime pay nor compensatory rest were due. The maximum number of relance voluntary overtime hours that an employee could perform was 120 hours per year. However, the combined maximum of "ordinary" and "relance" voluntary overtime hours could not exceed 220 hours per year.
What has changed under the new rules?
The total number of voluntary overtime hours that an employee is allowed to perform on a yearly basis has been increased from 220 hours ("ordinary" voluntary overtime hours and relance overtime hours) to 360 hours, now simply called "voluntary overtime hours".
Of these 360 hours, 240 are exempt from social security contributions and taxes (gross = net) and no overtime pay nor compensatory rest must be granted. Conversely, the remaining 120 hours are subject to social security contributions and taxes. They are also subject to overtime pay, but no compensatory rest is due.
Given the specific needs of the hospitality sector, the new Act provides for an even more favourable scheme. In this sector, the quota of voluntary overtime hours is increased to 450 hours.
What about part-time employees?
While the new system is generally more flexible, it imposes stricter conditions on part-time employees.
Under the new rules, a part-time employee will only be able to perform voluntary overtime hours if two cumulative conditions are met:
- The employee must have been working part-time for at least 3 years; and
- There must be a temporary increase in workload.
However, part-time employees who already had a voluntary overtime agreement in place with their employer on 1 June 2026 — i.e. the date of publication of the Act in the Belgian State Gazette — will not be subject to the aforementioned additional conditions.
Employees who reduce their working hours as part of a career break or thematic leave (e.g. time credit or parental leave) are specifically excluded from voluntary overtime.
Are any formalities required?
Voluntary overtime hours can only be performed on a voluntary basis and cannot be "imposed" by the employer.
To make use of voluntary overtime, the employer and employee must enter into a written agreement.
However, whilst under the "old" rules an agreement could only be entered into for a period of 6 months and each time needed to be renewed, such an agreement can now be entered into for a period of one year and will be tacitly renewed each year, unless the agreement is terminated by either party with one month's written notice. This change significantly reduces the administrative burden on employers.
Agreements concluded before 1 April 2026 for a period ending after that date will convert to an agreement under the new regime and remain valid until their initial expiration date.
What if I have used relance voluntary overtime hours during the first quarter of 2026?
The new regime of voluntary overtime hours — allowing employers to have their employees perform 360 voluntary overtime hours, of which 240 hours are paid on a net basis — entered into force on 1 April 2026.
For the first quarter of 2026, the "old" system of relance overtime hours was extended so that employers could have their employees perform 120 relance voluntary overtime hours during that quarter.
However, if the employer has made use of these relance voluntary overtime hours during the first quarter of 2026, then the number of relance hours used (maximum 120 hours) will be deducted from the 360 hours annual quota for 2026 under the new regime.
Key takeaways
The new rules on voluntary overtime hours provide more flexibility for employers, increasing the number of hours that can be performed under this system and reducing the administrative burden. The main changes can be summarised as follows:
- Annual quota: from 220 voluntary overtime hours per year (i.e. 100 "ordinary" + 120 relance voluntary overtime hours) to 360 voluntary overtime hours per year.
- Exemption from overtime pay, social security contributions and taxes: from 120 relance hours to 240 voluntary overtime hours.
- Compensatory rest: none due under either the old or the new rules.
- Part-time employees: from no specific conditions to two cumulative conditions — at least 3 years of part-time work and a temporary increase in workload.
- Written agreement: from a 6-month validity to a 1-year agreement, tacitly renewed each year, terminable on one month's notice.
Authors:
Esther Soetens, Counsel at ALTIUS
Christelle Umugwaneza, Associate at ALTIUS
