Sick leave in Belgium: guaranteed salary, relapses and who pays from day 31

For a white-collar employee who falls ill, the first 30 days of incapacity are paid by the employer at 100% of salary, and the health insurance fund (mutualité / ziekenfonds) pays from day 31. The employer’s share is called guaranteed salary (salaire garanti / gewaarborgd loon), and it is owed whether the illness lasts three days or three months.

The right to the full 30 days applies to an employee on an indefinite contract, and to fixed-term staff whose contract runs for three months or longer. In practice that covers almost every professional hire made through an employer of record, because most of them start on open-ended contracts.

Guaranteed salary is ordinary pay. It appears on the monthly payslip like any other working month, it is subject to the 13.07% employee contribution and to withholding tax, and it carries the full employer ONSS (RSZ) rate of 25.00% in 2026. A month off sick therefore costs the employer almost exactly what a month at work costs, without the work.

The point at which the cost stops is just as fixed. On day 31 the salary obligation ends and the employee claims a sickness allowance from the health insurance fund, which belongs to the national sickness and invalidity insurance supervised by the INAMI (RIZIV). The employment contract stays in force during that time; it is suspended, not ended.

Since 1 January 2026, a new period of incapacity that begins within eight weeks of the end of the previous one counts as a continuation of it, so the employer does not owe a fresh 30 days of guaranteed salary. Before that date the window was 14 days.

The change matters most for recurring conditions. Take an employee who is off for 20 days in February, returns for five weeks and then falls ill again in April. Under the old 14-day rule, April would have opened a new 30-day period at the employer’s expense. Under the 2026 rule, the April absence picks up where February stopped: the employer pays the 10 days that remain of the original 30, and the health insurance fund takes over after that.

Payroll has to track the dates carefully for this to work. The return-to-work date and the first day of each new certificate decide whether a period continues or restarts, so they need to be recorded on the day they happen rather than reconstructed at month end.

• Absence ends, employee returns: note the date.
• New illness more than eight weeks later: a fresh 30-day guaranteed salary period starts.
• New illness within eight weeks: the days already paid count against the same 30.
• Day 31 of the combined period: the health insurance fund pays the allowance.

A sick employee must send a medical certificate within the deadline set in the work regulations or a collective agreement, and if neither sets one, within two working days. Missing the deadline can cost the employee guaranteed salary for the days before the certificate arrives, which is why the rule should be written out clearly for staff.

Twice a year, an employee may be off for a single day without a certificate. The exemption covers only the first day of an incapacity, and only two occasions in a calendar year. Companies with fewer than 50 workers may opt out of this exemption and keep asking for a certificate from day one.

Where the rule lives is a practical question. Under a Belgian contract it sits in the work regulations (règlement de travail / arbeidsreglement), which every employer must have, together with the address for sending certificates and how the absence must be reported. Our guide to Belgian contracts and work regulations sets out what else that document has to contain.

For managers outside Belgium, the habit worth building is simple: when someone reports sick, ask them to send the certificate the same way every time and copy the payroll contact. A message to a line manager in another time zone is not a certificate.

Unlike sickness, most family leave in Belgium costs the employer little or nothing in salary, because the social security system pays the income during the leave. The employer’s job is to keep the post open, record the absence correctly and respect the protection against dismissal that comes with it.

• Maternity leave: 15 weeks as standard; a multiple birth extends it to 17, and in some cases 19. Up to six weeks can come before the birth, one of them compulsory. The health insurance fund pays the benefit, not the employer.
• Birth leave (congé de naissance / geboorteverlof): 20 days for the other parent, taken within four months of the birth. Days one to three come from the employer at full salary. From day four, benefit replaces 82% of the lost gross pay, paid by the health insurance fund.
• Parental leave: for each parent and each child, before the child turns 12. It can be taken as four months full-time, eight months half-time, 20 months at one fifth, or 40 months at one tenth, the last only with the employer’s agreement. A federal allowance from the ONEM (RVA) replaces part of the pay.

Pregnant employees are protected against dismissal from the moment the employer is told of the pregnancy until one month after postnatal leave, and dismissal linked to birth leave or parental leave is also protected. A termination in those windows needs reasons that have nothing to do with the leave, and the usual sanction for getting it wrong is a lump sum. The detail sits in our post on notice periods and dismissal in Belgium.

The employer’s exposure to any single illness is capped at one month of salary and contributions, and that makes sickness easy to budget compared with systems where sick pay runs for months. Our standard example shows the scale of it: a Brussels employee paid €4,500 a month under PC 200.

A full month off sick costs €4,500 in guaranteed salary plus €1,125 of employer ONSS at 25.00%, so €5,625 in total. From day 31 the employer pays no salary at all for the rest of the absence, however long it lasts, while the contract continues. A six-month illness therefore costs the employer one month, not six.

The 13th month (end-of-year bonus) deserves a check before December. Under PC 200 it equals one monthly salary, but the sector rules allow it to be reduced for some absences, so a long illness during the year may change the amount. The rules for the joint committee (PC) concerned, set out on the FPS Employment page on guaranteed salary and in the sector agreement, decide how.

The funding side explains why the employer’s share is so short. Of the 25.00% employer rate, 2.35 points are allocated to the sickness benefits branch in 2026, and the employee’s 13.07% includes another 1.15 points for the same purpose. The allowance from day 31 is paid out of that pot rather than by the company.

Not every day away from work is an illness, and the payroll treatment depends on which kind of absence it is. Three categories come up often enough that a manager outside Belgium should recognise them.

• Short absence leave (petit chômage / klein verlet): days off for family events such as a wedding or a funeral, with the number of days set by the type of event.
• Leave for compelling reasons: unpaid time off, up to 10 days a year, for urgent situations such as a sudden illness or accident in the family that needs the employee at home.
• Time credit (crédit-temps / tijdskrediet): under collective agreement no. 103, private-sector employees can suspend or reduce their work for set motives such as care or training, with an allowance from the ONEM (RVA) rather than salary.

Each of these is recorded differently in the quarterly DmfA, which is why a short note to payroll beats a calendar entry. Time credit in particular has motives, durations and age conditions that have changed several times, so check the current FPS Employment rules before agreeing a request.

Annual leave is separate again. Four weeks of paid holiday (20 days for someone working five days a week) are earned through the preceding year’s work, and 10 public holidays are added to them. Illness, family leave and annual leave each follow their own rules, and mixing them up on a timesheet leads to payslip corrections that are easy to avoid.

A practical test helps when a request comes in: ask who funds the day. If the employer pays full salary, it is guaranteed salary, annual leave or a public holiday. If a social security body pays, it is a longer sickness, maternity leave, most of birth leave, parental leave or time credit. If nobody pays, it is unpaid time off, such as leave for compelling reasons. That first question usually settles how the day appears on the payslip.

Once a person is hired through Employer of Record Belgium, guaranteed salary becomes part of our payroll: as their employer, we calculate it, pay it and declare it. You see it on the monthly invoice as part of the salary cost for that month, and the absence is reported in the quarterly DmfA like any other.

What we need from your side is information, quickly. The first day of absence, the date a certificate was received, and the return date are the three facts that decide whether the employer is still paying or the fund has taken over. If your managers approve leave in their own tools, agree a simple way to pass those dates on.

• Tell us on the first day an employee reports sick, not at month end.
• Forward certificates as soon as they arrive, with the period they cover.
• Let us know the return date, so the eight-week window can be tracked.
• Raise any plan to end the contract during or after a long illness before acting on it.

Long illnesses also raise questions about workload and replacement. A fixed-term replacement contract is possible, and the steps for any new hire are the same as in our walk-through from offer to first payslip. For a wider picture of what the employer role covers, see how the employer role is shared between you and us.