Before you start

National register number
A determination of whether you are a Belgian tax resident
itsme or an eID card reader, to use MyMinfin
Your employer's assessment of whether the inbound taxpayer regime applies

Step-by-step

1
Establish whether you are a Belgian tax resident
Residence turns on where your home and centre of economic interests sit, with entry in the population register creating a rebuttable presumption. Residents are taxed on worldwide income; non-residents only on Belgian-source income, on a different return.
OnlineWho: You
2
Raise the inbound taxpayer regime at contract stage
Under BBIB the employer can pay part of your gross remuneration as tax-free expense reimbursement. The employer applies within a short window after employment begins, and if the window closes the regime is unavailable for that engagement. This is a conversation for the offer, not the first payslip.
Via employerWho: Your employerAt hiring
3
Know the brackets and where 50% begins
For income year 2026 the rates are 25%, 40%, 45% and 50%, with the top rate from roughly €48,000 of taxable income and a basic tax-free allowance around €11,180. Employee social security of 13.07% is deducted from gross before income tax is calculated.
OnlineWho: You
4
Note Antwerp's communal surcharge
The additional communal tax is a percentage of the income tax you owe, voted by the city and published annually by FPS Finance. Antwerp charges 7.0% for assessment year 2026, against a national range from 0% in Knokke-Heist to 9.0% in Mesen. Your registered address on 1 January fixes the rate for that year.
OnlineWho: You
5
Check the proposed simplified return rather than ignoring it
Many employees receive a pre-filled proposal instead of a blank return. It still has to be checked and corrected — deductions the administration cannot see, such as childcare, pension savings or a foreign account, will simply be missing. Accepting a wrong proposal by silence is on you.
OnlineWho: YouLate April to mid-July
6
Declare foreign accounts, insurance and property
Belgian residents must report foreign bank accounts to the National Bank's central point of contact and declare foreign life insurance and foreign immovable property in the return, with foreign property valued on the same cadastral basis as Belgian property since the 2021 reform. This is among the most commonly missed obligations for new arrivals.
OnlineWho: You

Documents you’ll need

National register number and itsme or eID reader
Annual payslip summary (fiche 281.10)
Records of foreign accounts, insurance policies and property
Certificates for pension savings, childcare and mortgage deductions
Any inbound taxpayer regime confirmation

Things most newcomers don’t know

The pre-2022 Belgian expat regime no longer exists, and its replacement was rewritten for 2025.

The special regime for foreign executives was abolished on 1 January 2022 and replaced by the inbound taxpayer regime (BBIB) and inbound researcher regime (BBIO). For remuneration from 1 January 2025 the tax-free expense allowance rose from 30% to 35% of gross, the €90,000 annual cap was abolished, and the minimum gross salary condition fell from €75,000 to €70,000, with researchers subject to no salary minimum. Social security did not follow, so the 30% and €90,000 limits still apply for contributions and payroll now diverges from tax. Almost everything written online describes either the abolished regime or the 2022–2024 version.

Source: FPS Finance; professional-firm circulars on the 2025 reform

Antwerp's communal surcharge is 7.0%, and the national spread is wider than people assume.

The additional communal tax is levied on the tax you already owe, not on income, and each municipality sets its own rate. Antwerp charges 7.0% for assessment year 2026; the City of Brussels charges 4.9%, some coastal municipalities charge 3% or even nothing, and parts of Wallonia reach 8.8% or 9.0%. It is a real difference on identical income, it is published by FPS Finance every year, and it is decided by where you are registered on 1 January.

Source: FPS Finance — 2026 communal tax rates table

The simplified return is a proposal, not a settlement.

Belgium sends many employees a pre-completed proposal rather than a return to fill in. It is built from what the administration already knows — salary, withholding, mortgage data — and it will not contain what it cannot see: childcare costs, pension savings, charitable gifts, a foreign account, service vouchers. Silence is acceptance. Newcomers treat the proposal as a receipt and quietly overpay for years.

Source: FPS Finance

The employer, not you, applies for the inbound regime, and there is no second attempt.

The regime is claimed by the employer within a defined period of the employment starting. Miss that window and it is unavailable for that engagement, permanently — which for a benefit running up to five years and worth as much as 35% of gross as tax-free reimbursement is an expensive administrative oversight. Belgian HR teams that hire internationally know the deadline; a first-time hiring manager may not. Raise it explicitly during negotiation.

Source: FPS Finance

Common mistakes to avoid

Relying on anything written about the pre-2022 expat regime.
Letting the employer's window to apply for the inbound regime lapse.
Accepting the simplified return without adding deductions the administration cannot see.
Failing to declare foreign bank accounts, foreign life insurance or foreign property.
Budgeting from gross salary without allowing for 13.07% social security before tax.

Some of this may be out of date. Spotted something inaccurate? Help us keep it right for the next newcomer.