📌 In short: your self-employed status in Belgium does not change on its own. If your situation changes, for example you start or stop a regular job alongside your self-employment, you need to notify your social insurance fund. This article explains what changes and how.
Please note that this article provides general guidance only. Tax rules may vary depending on your individual situation. When in doubt, ask your Tax Coach.
This article covers the difference between the two statuses, how each one affects your social contributions and tax, and what steps to take when switching.
💡 What is the difference between the two?
Main activity: self-employment is your main job. You have no other significant employment.
Complementary activity: you are self-employed on the side, while also working as an employee, being a student, or receiving a pension. To qualify as a complementary activity, you need to work at least half-time in your main job (at least 19 hours per week).
🚨 Your status does not change automatically. You must contact your social insurance fund (Acerta, Xerius, Liantis, Securex, Partena, etc.) and declare the change yourself.
💶 How does it affect what you pay in social contributions?
Main activity | Complementary activity | |
Rate | About 20.5% of your income | About 20.5% of your income |
Minimum per quarter | About €890 | Very low or none below €1,922/year |
Social protection | Full (pension, sick pay, family benefits) | Limited, you rely on your employee rights |
ℹ️ As a complementary activity self-employed person, your contributions generally do not build up pension or sickness rights. This only changes if you earn more than about €17.374,08 from your self-employed activity.
🚀 Switching to main activity? You may pay less at the start
If you switch from complementary activity to main activity and were not registered as main activity in the past 5 years, you may qualify as a primostarter (starter reduction). This means lower contributions for your first 4 quarters, around €460 per quarter instead of €890, while still building full social rights.
📊 How does it affect your tax?
As a complementary activity self-employed person, your self-employed income is added on top of your salary and taxed at your highest tax rate, often 40 to 50%. It is important to keep this in mind when setting your rates as a freelancer.
👉 What to do when switching status
Contact your social insurance fund and tell them about the change and the date it takes effect.
Recalculate your quarterly contributions to avoid a surprise regularisation bill later.
Check whether you qualify for the starter reduction if switching to main activity.
💡 Not sure whether you qualify as a complementary activity? Contact your social insurance fund or our tax coaches. Being registered in the wrong status can lead to extra costs later.
Key takeaways
Your self-employed status in Belgium does not change automatically: you must notify your social insurance fund yourself.
Both statuses are taxed at the same rate (about 20.5%), but the minimum quarterly contribution is much higher for a main activity (about €890) than for a complementary activity.
Complementary activity income is taxed on top of your salary at your highest marginal rate, often 40 to 50%.
If you switch from complementary to main activity and have not been registered as main activity in the past 5 years, you may qualify for the primostarter reduction (around €460 per quarter for your first 4 quarters).
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