For employees and employers
Calculate the year-end bonus (Belgium)
How much of your year-end bonus do you keep, and what does it cost the employer? For employees and employers: personal social security, withholding tax at the 2026 rate for exceptional payments and employer social security contributions.
End-of-year bonus
| Breakdown | Amount |
|---|
The withholding percentage depends on the normal taxable annual salary (monthly salary after social security and work bonus × 12). Without exemption or reduction for dependent children.
Explanation: calculate the year-end bonus (Belgium)
The end-of-year bonus (13th month) is not required by law in Belgium, but it is usually granted through the joint committee or the company; it often equals a full month’s salary. On the bonus you pay 13.07% personal social security (RSZ), and the withholding tax follows the rate for exceptional payments from Annex III, depending on your normal annual salary. You can calculate your ordinary net salary with gross-to-net.
Frequently asked questions
Am I entitled to a year-end bonus?
Only if your joint committee, a company collective agreement or your employment contract provides for it. In many sectors it does; the amount and conditions (e.g. seniority or reference period) differ per joint committee.
How much withholding tax do I pay on my year-end bonus?
A fixed percentage that depends on your normal taxable annual salary: in 2026 from 0% up to €10,675 to 53.50% above €59,900. The percentage is applied to the bonus after deduction of 13.07% social security. Dependent children can give an exemption or reduction; these are not calculated here.
What does the year-end bonus cost the employer?
The gross bonus plus employer social security contributions (in this calculator 32.43% or 34.12% from 10 employees, without structural reduction).
How is a pro rata bonus calculated?
Anyone not employed for the whole reference year receives part of the bonus in many sectors, for example per month worked. Enter the number of months in the calculator; the exact rules are in your joint committee’s collective agreement.
Note: indicative, not advice
This calculation is an indication based on general statutory rules and 2026 rates and does not constitute tax, legal or payroll advice. The year-end bonus is not required by law; the amount and conditions follow from the joint committee, a company collective agreement or the employment contract. Withholding tax is an advance; the final tax follows from the tax return. Not included: dependent children (exemption/reduction), work bonus on the bonus, structural reduction, blue-collar workers (bonus via a fund) and year-end bonuses for piecework or task work (16.15%). No rights can be derived from this result.
Something wrong or missing? Let us know
Sources & values used
| Item | Amount | Status |
|---|---|---|
| Personal social security | 13.07% | RSZ/ONSS |
| Withholding tax on exceptional payments 2026 | 0% up to €10,675 · 23.22% · 25.23% · 30.28% · 35.33% · 38.36% · 40.38% · 43.41% · 46.44% (up to €45,860) · 51.48% (up to €59,900) · 53.50% | Annex III 2026 |
| Low-salary exemption (point 57) | no withholding tax if (annual salary + bonus)/12 would give no withholding tax | approximation |
| Employer social security | 32.43% (< 10 wn.) of 34,12% (≥ 10 wn.) | RSZ/ONSS 2026/3 |
| Reference salary | taxable monthly salary × 12 | approximation |
- FPS Finance – Calculating withholding tax (key formula from 1 January 2026, Annex III Royal Decree/ITC 92, Belgian Official Gazette 29-12-2025) (in Dutch)
- Social Security (socialsecurity.be) – Which contributions does an employer pay? (incl. 13.07% employee, structural reduction) (in Dutch)
- RSZ/ONSS – Administrative instructions 2026/3: social security contributions (basic contribution, wage moderation, special contributions) (in Dutch)
- FPS Employment – Search collective agreements (year-end bonus per joint committee) (in Dutch)
Checked on 6 October 2026.