Status check: 21 September 2026
The 2026 data are based on the RVO WBSO Guide 2026. The 2027 percentages have been announced; the increase to €33 is included in the Fiscale verzamelwet 2027 and remains subject to completion of the parliamentary process.
WBSO amounts 2026 — final
| Component | Amount/rate | Status |
|---|---|---|
| First bracket | 36% over a maximum of €391,020 | Final 2026 |
| First bracket, WBSO starter | 50% over a maximum of €391,020 | Final 2026 |
| Second bracket | 16% above €391,020 | Final 2026 |
| Fixed S&O hourly amount | €29 per R&D hour | Final 2026 |
| Fixed cost amount | €10 per hour up to and including 1,800 hours; €4 above that | Final 2026 |
| S&O deduction for self-employed professional | €15,979 | Final 2026 |
| Additional S&O starter deduction | €7,996 | Final 2026 |
The fixed S&O hourly amount and the hourly costs-and-expenditures allowance are different mechanisms. The hourly amount determines calculated S&O wages. The hourly costs-and-expenditures allowance adds an amount for costs and expenditures to the base.
Announced WBSO parameters for 2027
| Component | 2027 | Status on 21 September 2026 |
|---|---|---|
| First bracket | 36% up to €391,020 | Announced |
| First bracket, WBSO starter | 50% up to €391,020 | Announced |
| Second bracket | 16% above €391,020 | Announced |
| Fixed S&O hourly amount | €33 per R&D hour | Proposed in Fiscale verzamelwet 2027 |
| S&O deduction for self-employed professional | Not yet published as final | Pending |
The fixed hourly amount of €33 is intended for situations in which no calculated historical S&O hourly wage is available. This is separate from WBSO starter status and the higher starter rate of 50%.
Full explanation of WBSO 2027
Application deadlines
| Situation | Deadline | Explanation |
|---|---|---|
| Employer: start on 1 January 2027 | No later than 20 December 2026 | The application must be submitted before the start period. |
| Self-employed professional without staff: start on 1 January 2027 | No later than 1 January 2027 | A different application deadline applies to self-employed professionals. |
| Start later in the year | Apply in advance | WBSO cannot be applied for retrospectively. |
Always check the current RVO rules immediately before submission. If a deadline falls on a non-working day, do not assume without official confirmation that it automatically shifts.
Administration and retention periods
| Component | Period | Status |
|---|---|---|
| R&D hours registration | Within 10 working days after the day worked | RVO administrative rule |
| Project records | No later than within 2 months after each calendar quarter | RVO administrative rule |
| Retention of WBSO records | 7 years | Retention obligation |
| Statement of realisation for 2026 | No later than 31 March 2027 | Year-specific deadline |
Hours registration must correspond with holiday and sickness records. Project documents must show which technical activities, bottlenecks, tests and results were actually carried out.
When might a project qualify for WBSO?
- development of technically new physical products;
- development of technically new production processes;
- development of technically new software;
- technical-scientific research;
- in-house technical bottlenecks and solution approaches;
- activities carried out within the European Union by the applicant company.
Commercial novelty, applying existing software or normal engineering does not automatically constitute R&D. The technical uncertainty and in-house technical development must be apparent from the application.
Primary sources and management
This register is based on the RVO WBSO Guide 2026, current RVO WBSO information and, for the proposed hourly amount change, the Fiscale verzamelwet 2027.
Substantively reviewed by Peter Klaren, WBSO specialist since 2004. Changes are recorded in the separate WBSO change register.
View the change register Calculate your WBSO