How to Claim the Belgian R&D Tax Credit — Complete Guide
The complete guide to claiming Belgium's R&D tax exemption on researcher wages. Not a grant, but equally valuable — save up to 80% of withholding tax on every qualifying researcher's salary.
Ask Lucas about the R&D tax creditWhat is the Belgian R&D Tax Credit?
The Belgian R&D tax credit — officially the partial exemption from payment of withholding tax for researchers — allows companies to retain up to 80% of the wage withholding tax (bedrijfsvoorheffing / précompte professionnel) they would normally remit to the tax authorities for qualifying researchers. This is not a subsidy or grant: it is a tax mechanism that directly reduces your payroll cost for R&D personnel.
The exemption was introduced to make Belgium more competitive for knowledge-intensive activities. It applies regardless of your company's region, sector, or size. Whether you are a startup with two researchers or a multinational R&D centre with hundreds, the same rules apply. The exemption is claimed through your regular payroll filings — there is no separate application to a grant agency, no competitive evaluation, and no waiting period.
Why this is different from a grant
- ✓No application deadline — the exemption is available every payroll period, year-round
- ✓No competition — every qualifying company can claim it simultaneously
- ✓Rolling — you claim it on each payroll filing, not as a one-off project
- ✓No cap per company — the more qualifying researchers you employ, the more you save
Who qualifies for the R&D tax exemption?
The exemption is available to companies that employ researchers meeting specific qualification criteria. The researcher must hold a qualifying diploma: a master's degree or doctoral degree in exact sciences, applied sciences, medicine, veterinary medicine, pharmaceutical sciences, or certain engineering and technology fields. Alternatively, a researcher with at least 5 years of relevant R&D experience may qualify under the experience-based route.
The R&D activities themselves must meet the criteria defined by the Federal Public Service (FPS) Economy. The work must involve systematic research or experimental development aimed at increasing the stock of knowledge and using that knowledge to develop new applications. Routine testing, quality control, and standard engineering do not qualify.
The company must file a notification with FPS Finance (via Belspo) indicating which researchers and projects qualify. This notification is mandatory — you cannot claim the exemption retroactively without it.
How much is the R&D tax credit worth?
The exemption is 80% of the withholding tax on qualifying researchers' wages. Here is what that means at different salary levels:
| Annual gross salary | Approximate annual saving per researcher |
|---|---|
| €40,000 | €8,000 |
| €50,000 | €10,000 |
| €60,000 | €12,000 |
| €75,000 | €15,000 |
| €90,000 | €18,000 |
These are approximate figures based on standard withholding tax rates. Your actual saving depends on the researcher's exact tax situation and salary structure. For a company with 10 qualifying researchers at an average salary of €60,000, this means approximately €120,000 in annual savings — every year, without applying for a grant.
Step-by-step: how to claim the R&D tax exemption
Identify qualifying researchers
Review your workforce to identify employees who hold a qualifying STEM diploma (master's or doctoral level) or who have at least 5 years of documented R&D experience. Only researchers actively engaged in qualifying R&D activities are eligible.
Document their R&D activities
For each qualifying researcher, document the R&D projects they work on. The documentation must show that the work involves systematic investigation or experimental development aimed at new knowledge or applications. Keep project descriptions, time allocation records, and technical reports.
File the exemption on each payroll
Apply the 80% withholding tax exemption through your regular payroll processing. Your payroll provider or internal team calculates the exemption and retains the corresponding amount instead of remitting it to the tax authority. This happens every payroll period — monthly or bi-weekly.
Submit annual notification to FPS Finance via Belspo
Each year, file the mandatory notification with the Belgian Science Policy Office (Belspo) identifying your qualifying researchers, their diplomas, and the R&D projects they are assigned to. This notification is a legal requirement and must be submitted on time.
Keep documentation for 7 years
Maintain complete records of researcher qualifications, R&D project descriptions, time allocation, and payroll calculations for at least 7 years. The tax authorities can audit your claims at any time within this period.
Optional — combine with VLAIO O&O or other grants
The R&D tax exemption applies to the wage withholding tax, while grants like VLAIO O&O cover project costs. These operate on different bases and can be combined. Ask Lucas which grant programs complement the R&D tax credit for your specific situation.
Can you combine the R&D tax credit with grants?
| Program | Combinable? | Note |
|---|---|---|
| VLAIO O&O subsidie | Yes | Different base — the grant covers project costs, the tax credit covers wage withholding tax |
| Innoviris R&D grants | Yes | Different base — same principle as VLAIO, applicable in Brussels |
| SPW Chèques Entreprises | Yes | Different base — SPW covers consultancy/project costs, tax credit covers payroll |
| De minimis aid | Not applicable | The R&D tax exemption is not classified as de minimis aid — it has its own state aid framework |
5 tips for maximising the R&D tax credit
Audit your workforce for hidden qualifiers
Many companies undercount their qualifying researchers. Review all employees with STEM master's degrees — including software engineers, data scientists, biomedical researchers, and industrial engineers. If they spend part of their time on qualifying R&D, that portion is eligible.
Document R&D activities in real time
The biggest risk during a tax audit is insufficient documentation. Keep contemporaneous records: project plans, research logs, experiment results, and time sheets showing R&D allocation. Reconstructing documentation after the fact is difficult and less credible.
Use the experience-based route where applicable
Researchers without a qualifying diploma but with 5+ years of demonstrable R&D experience can qualify through the experience-based route. This is particularly valuable for self-taught developers and experienced engineers who entered R&D without a formal STEM master's.
File the Belspo notification on time every year
Missing the annual Belspo notification deadline can jeopardise your entire year's exemption. Set a calendar reminder well in advance. The notification must be filed before the statutory deadline — late filings are not accepted.
Stack with the innovation income deduction
If your R&D results in patented innovations, you can combine the wage tax exemption with the innovation income deduction (IID), which exempts up to 85% of qualifying innovation income from corporate tax. Together, these two measures create one of Europe's most competitive R&D tax frameworks.
Common mistakes to avoid
Claiming for non-qualifying activities
Routine software maintenance, standard quality testing, and regular engineering work do not qualify as R&D under the legal definition. The activities must involve genuine uncertainty and systematic investigation. Over-claiming is the primary reason for rejected exemptions during audits.
Forgetting the Belspo notification
The exemption requires an annual notification to the Belgian Science Policy Office. Companies that apply the payroll exemption without filing this notification are technically non-compliant and risk having the entire exemption reversed during an audit.
Poor time tracking for mixed-role researchers
Researchers who split their time between R&D and non-R&D activities must track their R&D hours accurately. The exemption only applies to the R&D portion of their work. Without credible time records, auditors may disallow the entire claim for that researcher.
Not keeping records for 7 years
Belgian tax authorities can audit R&D tax credit claims for up to 7 years. Companies that discard documentation after 3 or 5 years leave themselves exposed. Maintain digital archives of all diplomas, project descriptions, time sheets, and payroll calculations.
Frequently asked questions about the R&D tax credit
How much can I save with the Belgian R&D tax exemption?
The exemption covers 80% of the withholding tax on qualifying researchers' wages. For a researcher earning €60,000 gross annually, this means approximately €12,000 per year in savings. There is no cap per company — the more qualifying researchers you employ, the more you save.
Do I need to apply for the R&D tax credit like a grant?
No. The R&D tax exemption is claimed through your regular payroll filings. There is no grant application, no competitive evaluation, and no waiting for approval. You do need to file an annual notification with Belspo identifying your qualifying researchers and projects.
Which diplomas qualify for the R&D tax exemption?
Master's and doctoral degrees in exact sciences, applied sciences, medicine, veterinary science, pharmaceutical sciences, engineering, and certain technology fields qualify. Researchers without a qualifying diploma can use the experience-based route if they have at least 5 years of documented R&D experience.
Can I combine the R&D tax credit with VLAIO or Innoviris grants?
Yes. The tax exemption operates on a different base (wage withholding tax) than project grants (project costs). You can claim the R&D wage tax exemption for the same researchers whose salaries are included in a VLAIO or Innoviris grant budget, because the two measures cover different cost bases.
What happens if I get audited on my R&D tax credit claims?
The tax authorities will review your researcher qualifications, R&D project documentation, time allocation records, and Belspo notifications. If documentation is complete and activities genuinely qualify as R&D, audits are straightforward. Maintain records for at least 7 years.
Ready to claim the R&D tax credit?
Ask Lucas how to combine the R&D tax exemption with Belgian grants for maximum savings, or check your overall grant eligibility.