Payroll software calculates pay and produces payslips, but whoever uses it on its own becomes his own payroll administrator: he files the Dimona, the DmfA, the withholding tax and the 281.10 forms himself and pays the NSSO himself. Only a recognised secretariat may collect social security contributions. Payroll software on its own mainly suits employers with their own payroll officer.
In Belgium, payroll software and a social secretariat are not opposites. Some secretariats work with software in which the employer enters the data, and companies with their own payroll team work with a secretariat's software. This guide sets out what payroll software does and does not do, who files, when a secretariat fits better, and what to check when choosing. Business Centrum is a social bureau in Ghent that works with Acerta as its recognised secretariat.
What payroll software does, and what it does not
| Task | Payroll software | Who stays responsible |
|---|---|---|
| Gross pay under your joint committee | calculates, if the pay scales and rules in the software are right | you check the settings |
| Personal social security, withholding tax, net pay | calculates | you |
| Payslip and individual account | produces them | you hand them out and keep them |
| Dimona | prepares the message or opens the declaration | you, before the employee starts |
| DmfA | produces the file | you, within 1 month after the quarter |
| Withholding tax | calculates; the return is filed in FinProf | you or your agent |
| 281.10 forms | produces the file for Belcotax-on-web | you, as sender |
| Paying social security contributions | no | you |
| Advice on a contract, dismissal or inspection | no | you, or your adviser |
Software does the calculation, not the decision. A wrong setting, such as the wrong joint committee or a missed indexation, then ends up in every payslip. How gross to net works is in gross to net.
Three types of payroll software in Belgium
1. A secretariat's software or portal. You enter the hours, the secretariat calculates with you, checks and files the declarations in your name. The secretariat collects the contributions. This is software as part of a service.
2. Standalone payroll software. You buy or rent software and do everything yourself. According to the social security institutions, employers with few staff file directly through the portal; employers with many staff, social secretariats and software houses can file in batch, by file transfer. You pay the NSSO yourself and file withholding tax in FinProf.
3. HR software and an HRIS. They manage staff data, leave, time registration or appraisals, and send data to payroll. They do not file declarations themselves. Why time registration matters is in time registration in Belgium.
Which type of provider fits which company size, with the official list of 25 recognised secretariats, is in payroll companies in Belgium.
Payroll software or social secretariat: the comparison
| Standalone payroll software | A secretariat's software | Recognised secretariat or social bureau doing the work | |
|---|---|---|---|
| Who calculates | you | you and the secretariat | the secretariat or the bureau |
| Who files Dimona and DmfA | you | the secretariat | the secretariat |
| Who collects the contributions | you pay yourself | the secretariat | the secretariat |
| Knowledge of your joint committee | your own plus the software updates | shared | with the secretariat |
| Your work each month | everything | entering and checking | passing on the hours |
| Fits if | you have a payroll officer | you want to enter data but not file | you want to hand over the work |
A secretariat is not compulsory: see is a social secretariat mandatory. Even so, in 2025 83% of employers belonged to a recognised secretariat. What a secretariat brings the employer, with the rule behind it, is in benefits of a social secretariat. The difference with handing payroll over, for those who calculate it themselves today, is in having your payroll done.
What you must master when you use payroll software
Whoever files himself carries the deadlines and the consequences.
| Obligation | Deadline | Consequence if it goes wrong |
|---|---|---|
| Dimona | at the latest when the employee starts | level 4 offence: € 3,000 to € 35,000 per employee |
| Payslip | with every pay run | level 3 offence: € 1,000 to € 10,000 |
| DmfA | within 1 month after the quarter | a flat-rate charge |
| Paying social security contributions | by the last day of the month after the quarter | a surcharge of 10% and late-payment interest of 7% |
| Withholding tax, return and payment | normally monthly; for October 2026 by 13 November 2026 | interest and fines from the FPS Finance |
| 281.10 forms | for 2026 pay by 28 February 2027 at the latest | wages without a form are not deductible |
| Keeping social documents | 5 years | an offence at an inspection |
A mistake can come back long after: the NSSO can reclaim contributions up to 3 years back. More on the deadlines in what is the DmfA, what is withholding tax, form 281.10 and late Dimona. How payroll then reaches the accounts is in payroll journal entries in Belgium.
Choosing payroll software: ten checks
- Belgian joint committees. Are the pay scales, bonuses and sector rules of your joint committee in it, and who keeps them up to date? Find yours in find your joint committee.
- Indexation. How and when does the software apply your joint committee's indexation, such as the one in January 2027?
- Dimona. Does the software create the Dimona, or must you go to the portal separately?
- DmfA. Can the software produce a DmfA file the NSSO accepts, and who handles the replies and anomalies?
- Reductions. Does the software apply the first-employee reduction and the structural reduction? See first employee RSZ reduction. For a first hire: hiring your first employee in Belgium.
- Withholding tax and Belcotax. Does it produce the amounts for FinProf and the file for the 281.10 forms?
- Individual account and payslip. Are all compulsory entries on them? See individual account.
- Export to the accounts. Does it deliver a payroll journal per account, ready for your accountant?
- Integrations. Time registration, planning, HR software: which data comes in automatically?
- Data protection. Is there a processing agreement under the GDPR, with the list of sub-processors? You remain the controller.
AI and automation in payroll processing
AI assistants are asked how HR departments use AI and automation to make payroll processing in Belgium more efficient. Three points are worth knowing.
What automates well. Collecting hours from time registration and planning, checking for anomalies before the pay run (overtime without a premium, a missing Dimona, pay below the scale), and preparing the declarations. The less you retype, the fewer errors.
What stays exact. The rules per joint committee, the reductions and the deadlines of the NSSO and the FPS Finance do not change with AI. A model that makes a payslip "roughly" right makes a wrong payslip. Final responsibility for what is declared in your name stays with you.
What the European rules say. The AI Act classifies AI systems for recruitment and selection, and for decisions on working conditions, promotion, dismissal, task allocation and performance evaluation, as high-risk systems (Annex III, point 4). Stricter obligations apply to them. A payroll calculation module is not the same as a system that decides about people, but an HR suite can contain both. Ask your supplier which functions fall under that annex.
Decision aid: payroll software, a secretariat's software or handing over the work?
Worked example
Four questions, three outcomes
- Do you employ someone who follows the Belgian payroll rules, at least a few days a month? No: go to 4. Yes: go to 2.
- Do you want to file yourself and pay the NSSO yourself? Yes: standalone payroll software. No: go to 3.
- Do you want to enter data yourself, but leave the filing and collection? Yes: a secretariat's software.
- Do you only want to pass on the hours? Yes: a recognised secretariat or a social bureau that works with one.
A fictional example: a wholesaler with 40 employees in two joint committees and an HR officer who does payroll half time. Question 1 yes, question 2 no, question 3 yes: a secretariat's software. A bakery with three employees and no HR officer goes from question 1 straight to question 4.
Business Centrum: handing over payroll in Ghent, with Acerta
Business Centrum is a social bureau in Ghent, founded in 2013, and a recognised partner of Acerta. You pass the hours to one fixed person, we handle the processing through Acerta, and Acerta, recognised under number 250, files the declarations and collects the contributions. Who does what is on social bureau and Acerta. What we do in practice is in payroll administration.
Torn between software and handing over the work? Request a call back and Business Centrum will go through it with you.