The Belgian Payslip Explained (Gross to Net)

Your first Belgian payslip — the fiche de paie in French or loonfiche in Dutch — is a wall of abbreviations, and the number at the bottom is a lot smaller than the salary you agreed to. This guide walks you line by line from gross (brut / bruto) to net, so you understand exactly where the money goes and can spot an error.

The four steps from gross to net

Every Belgian payslip follows the same logic, in this order:

1. Start with your gross salary (salaire brut / brutoloon).
2. Subtract your personal social security contribution — a flat 13.07% (called ONSS in French, RSZ in Dutch).
3. Subtract withholding tax (précompte professionnel / bedrijfsvoorheffing) from what remains.
4. Add or subtract small items — meal-voucher contribution, transport, benefits — to reach your net (net à payer / netto).

Get these four steps and you can read any Belgian payslip.

Step 1 & 2: Gross minus 13.07% social security

The 13.07% employee social security contribution is the same for everyone, at every salary level, with no cap. It funds your healthcare, pension, unemployment cover and disability insurance. Your employer pays a much larger contribution on top (roughly 25% for white-collar staff), but that never appears as a deduction on your payslip — it sits above your gross.

For a €3,500 gross monthly salary:

• Social security: €3,500 × 13.07% = €457.45
• Taxable base after social security: €3,500 − €457.45 = €3,042.55

This taxable base is the figure the tax calculation works from — not your headline gross.

The work bonus for lower salaries

If you earn a modest salary, part of that 13.07% is handed back through the work bonus (bonus à l'emploi / werkbonus) — a reduction in your personal social security so you keep more net. Per the official ONSS instructions, from 1 April 2026:

• Full bonus applies up to a gross of €2,880.32/month, worth up to €125.04/month for employees.
• Between €2,880.32 and €3,336.98, the bonus tapers down.
• Above €3,336.98, no social work bonus applies.

There is also a separate fiscal work bonus (a reduction on your withholding tax and a refundable tax credit), with the cap raised to €765 for 2026. Our €3,500 example sits above the threshold, so it gets no work bonus — but if you earn under about €3,300 gross, expect a visibly higher net than the raw maths suggests. Check the exact amount at socialsecurity.be.

Step 3: Withholding tax (précompte professionnel)

The précompte professionnel / bedrijfsvoorheffing is not a special tax — it is a monthly advance on your annual income tax, deducted at source and settled when you file your yearly return. The amount depends on your taxable base, your family situation (single, married, dependent children), and official scales published by FPS Finance (fin.belgium.be).

Belgian income tax is progressive. For income year 2025 (assessment 2026), the national brackets are:

The first slice of income — a tax-free allowance (quotité exemptée) of €10,910 — is untaxed, and more if you have dependent children. On top of this, Belgian communes add a communal surcharge (additionnels communaux) of typically 0–9% of the tax due, which varies by the Brussels commune you live in.

For a single person with no children on €3,500 gross, the monthly withholding is roughly €650–€720 (approximate — the official scale is a per-person formula, so treat this as indicative and use the calculator below for a figure tailored to you).

That gives an approximate cash flow:

Your real number depends heavily on family situation and commune, so use this only as a shape, not a promise.

Try it yourself: our Brussels salary calculator turns a gross figure into an estimated net using these rules.

Step 4: The extras that top up your net

Belgian pay is not just the monthly cheque. Look for these:

• Meal vouchers (chèques-repas / maaltijdcheques): from 1 January 2026, up to €10 per day worked. Employer pays up to €8.91, you pay at least €1.09 — that small employee share shows as a deduction on your payslip. They are exempt from tax and social security when the conditions are met, so effectively free money.
• Double holiday pay (double pécule de vacances / dubbel vakantiegeld): a legal right. For white-collar staff it is about 92% of one month's gross, paid once a year, usually in May or June — a big extra pay-out separate from your normal salary while on leave.
• 13th month (prime de fin d'année): a bonus usually paid in December — but not guaranteed by law. Whether you get one, and how much, depends on your joint committee (commission paritaire / paritair comité) or your contract.
• Transport reimbursement, eco-vouchers, and any company car / meal / insurance benefits, which may appear as a benefit in kind (avantage de toute nature / voordeel van alle aard) and can be partly taxed.

Common problems and fixes

• "My net looks too low." First check the withholding is set for the right family situation — being taxed as single when you have dependent children costs you every month. Ask HR or your social secretariat (secrétariat social) to correct it; over-withholding is refunded when you file, but why wait.
• "I never got a 13th month." It is sector-dependent. Find your joint committee number (PC/CP) on your contract or payslip and check that committee's rules — if it provides one, you are owed it.
• "The work bonus isn't on my payslip." It only applies below roughly €3,337 gross/month. Above that, there is nothing to show.
• "My first payslip has odd part-month figures." Starting mid-month prorates both salary and deductions. It should normalise the following full month.
• Missing or wrong meal vouchers? Confirm the daily value and that your employee share matches (€1.09 for a €10 voucher). Raise it with HR early — corrections get harder after year-end.

One concrete next step

Take your signed contract, find your gross monthly salary and your family situation, and run them through the Brussels salary calculator to get your estimated net. Then, on your first real payslip, tick off the four lines — gross, 13.07% social security, withholding tax, extras — and confirm they match. If the withholding looks off for your family situation, email your HR or social secretariat straight away to fix it. For anything unusual, the official rules live at socialsecurity.be and fin.belgium.be.