Understand · Payroll glossary
What are employee social security contributions?
Updated on
Employee social security contributions are the part of your gross salary paid to social security: 13.07% for a private sector employee. In Dutch: werknemersbijdragen.
Definition of employee social security contributions
They fund your rights: 7.50% goes to pensions, 3.55% to health care, 1.15% to sickness and invalidity benefits and 0.87% to unemployment. Your employer deducts them from your gross pay and pays them to the National Social Security Office (NSSO).
For a blue-collar worker, they are calculated on 108% of gross pay, because their holiday pay is paid separately by a holiday fund. Low wages get part of them back through the work bonus.
The key figure in 2026
Source: Instructions administratives : les cotisations de sécurité sociale, National Social Security Office (NSSO). Value in force on 1 October 2026.
Worked example
At €2,500 gross, the theoretical contributions are €326.75. The work bonus refunds €245.72 of them: only €81.03 in contributions is actually deducted. At €4,000 gross, there is no bonus any more: the full €522.80 is deducted.
In Dutch: werknemersbijdragen
On a Dutch-language payslip (loonbrief), employee social security contributions are called ‘werknemersbijdragen’ or ‘RSZ-bijdrage’; on a French-language one (fiche de paie), ‘cotisations sociales personnelles’ or ‘cotisation ONSS’. In English: employee social security contributions.
Not to be confused with…
- Employer social security contributions: the social security contributions your employer pays on top of your gross salary; they are not deducted from your pay.
- Special social security contribution: a monthly deduction on top of social security contributions, from 0 to €60.94 a month depending on your salary and household.
Calculate it for your situation
Every line of a Belgian payslip explained, with its Dutch label and a worked example.
Related terms
- NSSOFrom gross to net · in Dutch: RSZ (Rijksdienst voor Sociale Zekerheid)
- Work bonusFrom gross to net · in Dutch: werkbonus
- Statutory civil servantPublic sector and education · in Dutch: statutair personeelslid
Sources
Parameters in force on 1 October 2026. Each parameter links to its source, the official one where it exists; a secondary source is flagged as such.
- Instructions administratives : les cotisations de sécurité sociale, NSSO. Cross-checked with: UCM, Securex and the FEB (via the Walloon Public Service) for the basic employer rate in the private sector: 19.88% basic contribution and 5.12% wage moderation contribution, making 25%.
- Administratieve instructies: bijdragen, NSSO.
- Loonbrief onder de loep 2026 (Dutch-language payslip guide), CSC/ACV (secondary source).