Checklist: the hidden costs of absenteeism

1. Direct costs

Costs that follow directly from the employee's absence

Gross salary of the employee on sick leave
*On average you keep paying 30 days of salary for short-term absence, even with no productivity in return.

Employer social security contributions (RSZ) during illness
Social security contributions keep running while the employee is absent: on average 25% on top of the gross salary.

Guaranteed salary (first month)
*Employers bear the full cost in the first month of illness, especially for stress-related absence such as burnout or depression.

2. Replacement costs

Costs of getting the work done anyway.

Hiring a temporary replacement
Temporary staff, freelancers or interims cost on average 15–30% more per hour than permanent staff.

Overtime or extra workload for colleagues
Team members have to step in, which leads to higher stress levels and a risk of further absence.

Lost productivity in the team
Research shows that a team works 20–30% less efficiently when a key employee is absent for a long time.

Training or onboarding a replacement
*Onboarding a new person takes time from other colleagues, which raises the indirect cost further.

3. Indirect costs

Hard to measure, but side effects with real impact.

Delays to projects or deadlines
Schedules have to be adjusted, which drags down performance and affects customer satisfaction.

Loss of expertise / knowledge
Especially with senior profiles: their knowledge is often not easy to pass on.

Loss of quality or mistakes
Stress, time pressure and understaffing lead more quickly to mistakes or missed opportunities.

Customer dissatisfaction or damage to your image
*Unexpected delays or communication problems caused by the absence of key employees can damage your reputation.

4. Organizational costs

The time and energy HR and managers spend.

Time spent by HR or managers
On average 2–6 hours of administration, follow-up and meetings per absent employee per month.

Administrative follow-up and schedule changes
Contract management, sick notes, return-to-work plans, back-up tasks...

Legal risks with long-term absence
*Absence files require a correct approach and communication. Mistakes can lead to sanctions or conflicts.

5. Psychological and cultural impact

The effect on the team and the working atmosphere.

Dip in colleagues' morale
Teams under constant pressure more often feel frustration, fatigue or lower engagement.

Knock-on effect: a 2nd wave of absence
When one employee drops out, the risk rises that others in the team drop out too, because of extra workload or negativity.

Loss of trust in policy or leadership
*If no structural solution comes, belief in HR or management initiatives drops.

6. Missed opportunities

What you miss by fighting fires instead of building.

Innovation or improvement projects put on hold
HR or team leaders have less time for strategic work when absence management takes priority.

Delays in culture, wellbeing or DEI projects
Projects that really engage and motivate employees are too often left on the shelf.

Damage to your employer brand
High absence gets noticed inside and outside the company, which undermines recruitment and retention.

**

Recommendation**

Have HR, finance and management go through this checklist together. Every ticked box is a hidden cost. Add them up, and ask yourself: What does doing nothing cost?

Would you like concrete ideas to lower these costs for your organization? Book a short wellbeing review session, and we will look at the options together.

Sources:
Belgian labour law, 2025
Health survey IDEWE, 2022.