Annex III: a few words of explanation
The professional withholding tax on salaries, the RCC, and pensions is indexed every year and adjusted to the new legislation. This adjustment is made through the “Annex III”, the third annex of the AR/CIR 92, which outlines the rules regarding the professional withholding tax.
The key formula for the automatic processing of the calculation of the professional withholding tax is also updated via Annex III.
What are the new features for 2026?
In addition to the classic indexing of several amounts, some new features have been introduced this year.
Higher net salary in 2026 due to a reduction in the professional withholding tax.
Since 2023, the calculation of the professional withholding tax has been structurally adjusted to better account for inflation. This adjustment will continue to apply in 2026.
Thus, the scales of the professional withholding tax are primarily automatically adjusted for inflation.
Furthermore, “progressive scales” have been used since 2023. This means that the taxable amount of remuneration, pensions, or RCC allowances is no longer rounded down to the nearest multiple of 15 euros to determine the professional withholding tax (previous scales I, II, and III). A key formula is now used to perform the calculation, allowing the professional withholding tax to increase in a more gradual and proportional manner.
Given these adjustments, a larger portion of the salary will be subject to a lower rate in 2026 as well, enabling your workers to keep a higher net amount. The exact amount depends on the level of income and family situation.
Here are a few examples for illustration:
Example 1
Pierre earns 2,800 euros gross. He is married, and his partner has their own income. The couple has no children. Let’s compare the professional withholding tax withheld monthly on Pierre's salary in 2025 with that which will be withheld in 2026.
| Income year 2026 | Income year 2025 | |
| Gross | 2,800 | 2,800 |
| Social Security | -365.96 | -365.96 |
| Employment Bonus | 115.17 | 115.17 |
| Taxable | 2,549.21 | 2,549.21 |
| professional withholding tax | -363.90 | -380.26 |
| Net | 2,186 | 2,169 |
As you can see, in 2026, Pierre will earn 17 euros net more per month compared to 2025.
Example 2
Petra earns 4,000 euros gross. She is married, and her partner does not have their own income. The couple has one child. Let’s compare the professional withholding tax withheld monthly on Petra's salary in 2025 with that which will be withheld in 2026.
| Income year 2026 | Income year 2025 | |
| Gross | 4,000 | 4,000 |
| Social Security | -522.8 | -522.8 |
| Taxable | 3,477.2 | 3,477.2 |
| professional withholding tax | -355.18 | -378 |
| Net | 3,123 | 3,099.20 |
As you can see, in 2026, Petra will earn 23.80 euros net more per month compared to 2025.
Tax advantageous overtime: general quota
Workers and employers benefit from a tax advantageous scheme for a certain number of overtime hours per year. The advantage of this scheme is twofold:
- For the employer: an exemption from the payment of the professional withholding tax
- For the worker: a reduction in the professional withholding tax
In general, a quota of 130 overtime hours per year per worker applies (for all sectors, except construction and horeca). This ceiling has been temporarily raised several times to 180 overtime hours; the last time until 31 December 2025.
Learn more: “Program law published: the recovery overtime and the tax advantageous overtime officially extended until the end of 2025”
However, the authorities wish to perpetuate this temporary increase to 180 hours (probably from 1st January 2026). In the absence of legislation on this matter, Annex III again mentions a general quota of 130 hours for 2026.
We will keep you informed as soon as we know more about this.
Student work
Since 2025, no professional withholding tax is due on the first 650 hours of student work per calendar year.
Learn more: “Students can work up to 650 hours per year”
This modification has now been made to the text of Annex III.
What does Securex do for you?
We adapt, as every year, the aforementioned modifications in our calculation system to ensure you a precise salary calculation in 2026.
For any other questions regarding the professional withholding tax, do not hesitate to contact your Securex Legal Advisor at the following address: myhr@securex.bemailto:myHR@securex.be.
Additionally, you can also contact us on the MySecurex online portal. The “MySupport” search function allows you to consult the most frequently asked questions and their answers. This way, you will receive assistance quickly, even outside office hours.
Source
Royal decree of 11 December 2025 amending, regarding the professional withholding tax, the AR/CIR 92, Moniteur belge of 29 December
