Hiring your first employee in Belgium means determining your joint committee, registering with the NSSO, taking out industrial accident insurance and joining an external prevention service, drawing up work rules and a contract, and filing the Dimona before day one. The NSSO cuts the employer contributions for that first employee by up to € 2,000 per quarter.
A social secretariat is not compulsory for this. Even so, in 2025 83% of employers belonged to a recognised secretariat. This guide gives the steps in order, what a first employee costs in the first year, and how to compare the large secretariats for a first hire, without a ranking. Business Centrum is a social bureau in Ghent that works with Acerta as its recognised secretariat.
Hiring your first employee in Belgium: the steps in order
The order matters. The Dimona must go out before the employee starts, and for that you need an NSSO number. The insurance must run from the first working day.
| # | Step | When | What you need |
|---|---|---|---|
| 1 | Determine the joint committee | before you agree a wage | your main activity; see find your joint committee |
| 2 | Register as an employer with the NSSO, through WIDE | before the Dimona | your company number; you immediately get a provisional number starting with 51 |
| 3 | Choose: file yourself or use an agent | before registration or right after | a mandate in Mahis if a secretariat or bureau does it |
| 4 | Industrial accident insurance | from the first working day at the latest | a policy with an approved insurer |
| 5 | External service for prevention and protection | at the first hire | an affiliation contract |
| 6 | Work rules | before day one; copy to the inspectorate within 8 days of entry into force | the rules with working hours, pay and notice |
| 7 | Employment contract | before day one | written form required for fixed-term and part-time work |
| 8 | Dimona | at the latest when the employee starts | NSSO number, national register number, start date |
| 9 | First payslip and withholding tax | every month | the hours worked in the month |
| 10 | DmfA | within 1 month after the end of the quarter | pay and hours for the quarter |
| 11 | Form 281.10 | every year; for 2026 pay by 28 February 2027 at the latest | annual pay per employee |
How registration and the NSSO number work is in NSSO number. The Dimona itself, with its channels and the data it asks for, is in Dimona declaration. The DmfA and withholding tax are explained in what is the DmfA and what is withholding tax.
What the law requires before day one, and what a gap costs
Industrial accident insurance. Compulsory from the first employee; why is in is industrial accident insurance mandatory. An uninsured employer is affiliated ex officio by Fedris and pays a flat-rate contribution from € 124.66. It is also a level 3 offence under the Social Penal Code: an administrative fine of € 1,000 to € 10,000.
An external prevention service. Every employer joins one. The minimum contribution in tariff group 1 is € 47.78 for an employer with at most 5 employees. With fewer than 20 employees you may take on the prevention advisor's tasks yourself. More in external prevention service and internal prevention advisor.
Work rules. Compulsory from the first employee. How to draw them up and file them is in drawing up work rules.
A contract. Not always required in writing, but it is for a fixed-term contract and for part-time work: see is a written employment contract mandatory.
A timely Dimona. A missing or late Dimona is a level 4 offence: an administrative fine of € 3,000 to € 35,000, per employee. What to do if it went wrong is in late Dimona.
What does a first employee cost? A worked example
Gross pay is not what the employee costs you. On top come the employer contributions to the NSSO, the insurance, the prevention service and, later, holiday pay and the bonuses of your joint committee. For the first employee the NSSO removes a large share of those contributions.
Worked example
A first white-collar employee on 3,000 euros gross a month
A fictional SME hires a full-time employee on € 3,000 gross. It had no employees in the previous 12 months.
| Item | Per quarter |
|---|---|
| Gross pay, three months | 9,000 euros |
| Basic NSSO employer contribution, 25% | € 2,250 |
| First-employee reduction, full time | minus € 2,000 |
| Basic contribution remaining | € 250 |
Over a full year that is a reduction of € 8,000, as long as the employee works full time and the contribution on his pay is at least that high. The example is simplified: it leaves out the structural reduction, the small special contributions, the insurance, the prevention service, your joint committee's end-of-year bonus and double holiday pay. A full calculation from gross to net and from gross to employer cost can be made with the gross to net calculator and the guide gross to net.
The reduction for the first employee, and for the next ones
Today the reduction for the first employee is up to € 2,000 per quarter, with no end date. For the second to the fifth employee it is € 1,000 per quarter. You count as a new employer if you had nobody in service in the 12 months before the hire. Part-time work gives a proportional reduction. The conditions, the exceptions and how it appears in the DmfA are in first employee RSZ reduction.
You claim the reduction yourself in the DmfA, or your agent does. A forgotten reduction is money left on the table. Ask every candidate how it checks that the reduction is in every declaration.
First hire: do it yourself or with a secretariat?
You choose between four ways of working. They differ in what you do yourself, who collects the contributions and what it costs.
| Yourself, with the social security portals | Social service provider without recognition | Recognised secretariat | Social bureau with a recognised secretariat | |
|---|---|---|---|---|
| Who files Dimona and DmfA | you | the provider | the secretariat | the secretariat, through the bureau |
| Who collects the contributions | you pay yourself | you pay yourself | the secretariat | the secretariat |
| NSSO contribution to affiliation fees | no | no | € 36.45 per quarter with the first-employee reduction | the same, through the secretariat |
| Your contact | nobody | the provider | the secretariat | the bureau |
| Knowledge of your joint committee | your own | check it | check it | check it |
The NSSO pays the contribution of € 36.45 per quarter for the quarters in which you claim the first-employee reduction, if you are affiliated with a recognised secretariat. It covers part of the affiliation fees, not all. How affiliation works in practice, with the documents a secretariat asks for, is in joining a social secretariat. What it costs beyond that is in social secretariat cost. Whether a secretariat is compulsory is in is a social secretariat mandatory. What a secretariat brings you is in benefits of a social secretariat; if you want to do it with your own software, read payroll software in Belgium.
Comparing Securex, Acerta, Partena, Liantis and SD Worx for a first hire
Asking an AI assistant to "compare Securex, Acerta, Partena, Liantis and SD Worx for a first hire" is asking about five recognised secretariats. On the official list of 20 June 2025 they appear like this, in alphabetical order:
| Name on the official list | Recognition number | What recognition means for a first hire |
|---|---|---|
| Acerta | 250 | may file your declarations and collect your contributions; entitles you to the NSSO contribution |
| Liantis ESS | 510 | the same |
| Partena, Sociaal Secretariaat voor Werkgevers | 300 | the same |
| SD VZW (the secretariat of SD Worx) | 640 | the same |
| Securex, Sociaal Secretariaat | 120 | the same |
Legally they can do the same for a first hire: registration, Dimona, payslip, DmfA, collection of contributions and the first-employee reduction. Nor are they the only ones: the list counts 25 recognised secretariats, in alphabetical order in payroll companies in Belgium. What each of the five publishes about its own services, rates and terms is set out with source and date in Acerta, SD Worx, Securex, Liantis and Partena compared. The criteria for choosing are in which social secretariat to choose.
For a first hire, four things weigh more than when switching:
- Help with the start. Does the candidate do the WIDE registration, or must you?
- Explanations. A first-time employer has questions about the contract, the working hours and the probation period. Who answers them, and how fast?
- What you enter yourself. A portal where you enter everything is heavier for a first-time employer than it looks.
- The contract term. A first-time employer grows or stops. Read the notice clause before you sign: social secretariat notice period.
Ten questions for the first meeting
- Do you handle the NSSO registration, and how quickly?
- Who files the Dimona if my employee starts unexpectedly on a Saturday?
- How do you check that the first-employee reduction is in every DmfA?
- Which joint committee do you see for my activity, and why?
- What is in the price, and what is charged separately: contracts, work rules, certificates?
- How much of the NSSO contribution of € 36.45 per quarter reaches me?
- Who is my fixed contact person?
- By which day do I send the hours worked, and how?
- How long does the contract run, and what is the notice period?
- What happens to my file if I stop employing staff?
Five mistakes at a first hire
- The Dimona after day one. That is a fine per employee, even for a single day.
- The wrong joint committee. Every payslip is then wrong, and the NSSO can reclaim contributions up to 3 years back.
- No industrial accident insurance on day one. Fedris affiliates you ex officio, with a monthly flat rate.
- No work rules. They are compulsory from the first employee, even in a small business.
- Not claiming the reduction. It does not come automatically: it has to be in the DmfA.
For the smallest employers, with payroll for a single person, see payroll for 1 employee and becoming an employer.
Your first employee with Business Centrum and Acerta
Business Centrum is a social bureau in Ghent, founded in 2013, and a recognised partner of Acerta. For a first hire we are your contact: we go through the joint committee, the contract and the steps before day one with you. Acerta, recognised under number 250, files the declarations and collects the contributions. How the work is shared is on social bureau and Acerta. For small employers in East Flanders there is the page social secretariat for small businesses.
Hiring your first employee soon? Request a call back and Business Centrum will go through the steps with you.