Notice periods and termination in Belgium: The Claeys Formula explained

Terminating an employee in Belgium can trigger notice obligations measured in months rather than weeks. For foreign employers, the complexity goes beyond the statutory schedule itself. Notice calculations can change depending on when the employee was hired, historical salary classifications may still affect long-tenured workers, and transitional rules from the 2014 labour-law reforms continue to shape dismissal costs more than a decade later.

The Claeys Formula, although never formally codified into law, still appears in legacy disputes, contractual notice clauses, and transitional calculations involving pre-2014 employment relationships. Combined with long notice periods, outplacement obligations, and protected-category indemnities, Belgian termination law remains one of the more financially sensitive areas of employing workers in Belgium.

Since 1 January 2014, the Unified Status Act replaced the old blue-collar/white-collar divide with a single seniority-based schedule. For any employee whose contract started on or after that date, notice depends on one variable only: uninterrupted length of service with the employer at the time of dismissal. Age, salary level, and functional classification are irrelevant.

The schedule is set by Article 37/2 of the Act of 3 July 1978 on Employment Agreements, as amended. Notice periods are expressed in weeks and begin on the Monday following the week in which notice is given.

Employees whose contracts predate 1 January 2014 are not governed by the post-2014 schedule alone. Belgian law applies a two-step calculation known as the “double photo” (dubbele foto / double photo), summing the notice entitlement from two distinct periods.

The Claeys Formula is a doctrinal calculation tool developed by Belgian employment law practitioner Thierry Claeys. It is not a statute and was never codified into Belgian law. Its authority derives from systematic statistical analysis of Belgian labour court judgments on notice periods for higher white-collar employees, published in periodic editions (1974, 2008, 2011).

Before 1 January 2014, Belgian statute did not prescribe exact notice periods for white-collar employees earning above the applicable salary threshold. The Act of 3 July 1978 required only that notice be adequate, courts applied a fact-specific proportionality analysis, and the Claeys Formula became the standard pre-negotiation benchmark for both parties.

Belgian law allows the dismissing party to either:

• Serve notice, allowing the employee to continue working during the notice period.
• Pay an indemnity in lieu of notice equal to the remuneration the employee would have earned during that period.

Under Article 39 of the Employment Agreements Act, the two options are alternatives rather than cumulative entitlements.

For employers, the financial exposure extends beyond base salary. The indemnity calculation includes the employee’s full remuneration package, including:

• Base salary
• Variable compensation
• Company car benefit in kind
• Meal vouchers
• Group insurance premiums
• Other contractual benefits

A 60-week notice period for a senior employee earning EUR 120,000 annually can produce an indemnity exceeding EUR 138,000 before employer social security contributions.

Dismissal for serious cause (motif grave / dringende reden) is the only route to immediate termination without notice or indemnity. Belgian law defines serious cause as a shortcoming by one party that renders any further professional collaboration immediately and definitively impossible.

The procedural requirements are strict and sequential. Failure to follow them converts the dismissal into an ordinary termination, exposing the employer to the full notice indemnity.

1. The employer must act within 3 working days of becoming aware of the facts constituting the serious cause.
2. Within a further 3 working days of the dismissal itself, the employer must communicate the reasons by registered letter, bailiff’s writ, or signed delivery receipt.

The Hof van Cassatie / Cour de cassation confirmed in February 2023 that the assessment of gravity must consider all circumstances, including but not requiring evidence of actual damages resulting from the shortcoming. Missing either deadline by even a single day typically renders the serious-cause dismissal unlawful.

Outplacement is a mandatory legal entitlement triggered by the notice infrastructure, not a discretionary employer benefit. Two situations activate the obligation.

• Notice period of 30 weeks or more (reached at approximately 9 years of seniority under the post-2014 schedule): all dismissed employees regardless of age are entitled to a 60-hour outplacement programme. The employer must make the offer within 15 days of dismissal. The cost, equivalent to 4 weeks of salary with a minimum of EUR 1,800 and a maximum of EUR 5,500, is deducted from the termination indemnity.
• Employee aged 45 or over at dismissal with at least 1 year of continuous seniority: entitled to outplacement under the residual older regime, applicable only where the employee does not qualify under the 30-week rule.

Outplacement does not apply to dismissals for serious cause. Employers who fail to offer outplacement within the 15-day window lose the right to deduct the cost from the indemnity but remain liable for the obligation.

Certain categories of employees in Belgium benefit from protection that goes beyond ordinary notice or indemnity entitlements. Dismissing these employees without following prescribed procedures triggers protection indemnities that can dwarf the standard notice cost.

The scale of protection indemnities for employee representatives is particularly significant. A union delegate dismissed without proper authorisation can claim up to 8 years of gross remuneration on top of any notice entitlement. For companies unfamiliar with Belgian compliance requirements, this is the category most likely to produce an unexpected six- or seven-figure liability.

Belgian notice law is not static, and two reforms adopted or pending in 2026 will reshape the calculation for future hires.