Social contributions of the self-employed in Belgium
Every Belgian sole trader pays social contributions to INASTI through a social insurance fund. These fund the pension, health and disability insurance, family allowances and bridging right. They are computed on the net taxable professional income and are, together with personal income tax, the main gap between turnover and disposable income.
1. Legal basis and institution
The social status of the self-employed is governed by Royal Decree no. 38 of 27 July 1967. INASTI supervises it; computation and collection go through an approved social insurance fund chosen by the self-employed person.
The fund adds management fees (typically around 4%), free and separate from the legal schedule. This tool separates them explicitly from the official contribution.
2. Rate and income brackets
The contribution is computed on the annual net professional income (turnover minus professional expenses). The ordinary rate is about 20.5% on the first bracket, then a reduced rate on a higher bracket, and nil above a high cap.
The exact bracket bounds and rates are indexed yearly and published by INASTI; this tool reads them from the official published schedule, with no approximated value.
3. Minimum and maximum contribution
In a main activity a minimum quarterly contribution is due even without sufficient income. A maximum quarterly contribution caps high earners' contribution.
In a secondary activity no contribution is due below an annual threshold; above it the ordinary schedule applies.
4. Primostarter and assisting spouse
The primostarter (start of a main activity) may, under income conditions, benefit from reduced provisional contributions during the first quarters.
The assisting spouse falls under a specific status (maxi status) with its own minima. Each category has its own rules, integrated in the calculation.
5. Provisional and reconciliation
Contributions are first paid provisionally based on a reference income, then reconciled once the actual income is known (usually two to three years later).
Social contributions are tax-deductible: they reduce the personal income tax base, which this calculator accounts for.