Understand · Payroll glossary
What is the special social security contribution?
Updated on
The special social security contribution is a monthly deduction on top of social security contributions, from 0 to €60.94 a month depending on your salary and household. In Dutch: bijzondere bijdrage voor de sociale zekerheid.
Definition of the special social security contribution
It is deducted every month by the employer, based on your salary and household situation (single, single-income or dual-income couple). It is not due on the lowest salaries and is capped for high salaries.
The amount deducted is an advance: the final contribution is recalculated with the annual tax, on the household’s actual income, and appears on the tax assessment notice (aanslagbiljet / avertissement-extrait de rôle). From 1 January 2028, it will be calculated per person.
The key figure in 2026
Source: La cotisation spéciale pour la sécurité sociale, National Social Security Office (NSSO). Value in force on 1 October 2026.
Worked example
| Gross | Single | Dual-income couple |
|---|---|---|
| €2,000 | €2.30 | €5.15 |
| €3,000 | €19.24 | €23.35 |
| €4,000 | €36.24 | €34.35 |
| €6,500 | €60.94 | €51.64 |
In Dutch: bijzondere bijdrage voor de sociale zekerheid
On a Dutch-language payslip (loonbrief), the special social security contribution is called ‘bijzondere bijdrage voor de sociale zekerheid’; on a French-language one (fiche de paie), ‘cotisation spéciale de sécurité sociale’. On Indexo’s English pages: special social security contribution.
Dutch term taken from: FPS Finance, CSC/ACV (secondary source).
Not to be confused with…
- Employee social security contributions: the part of your gross salary paid to social security: 13.07% for a private sector employee.
- Solidarity contribution: a reduced social security contribution that replaces the usual contributions, for example 2.71% for a student job.
Calculate it for your situation
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Related terms
- NSSOFrom gross to net · in Dutch: RSZ (Rijksdienst voor Sociale Zekerheid)
- Withholding taxFrom gross to net · in Dutch: bedrijfsvoorheffing
- Tax assessment noticeTax and tax return · in Dutch: aanslagbiljet
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.
- La cotisation spéciale pour la sécurité sociale, NSSO.
- Réforme de l’impôt des personnes physiques : impact sur la rémunération (28 August 2026), Attentia (secondary source).
- Toelichting bij deel 1 van de aangifte in de personenbelasting, aanslagjaar 2026 (Vlaams Gewest), FPS Finance.
- Loonbrief onder de loep 2026 (Dutch-language payslip guide), CSC/ACV (secondary source).