The monthly professional withholding tax in Belgium
The professional withholding tax is the income tax withheld at source by the employer on the worker's taxable salary. It is an advance on the personal income tax computed at year-end. Its amount depends on the taxable salary, family situation and dependents.
1. Legal basis and schedule publication
The withholding tax is governed by articles 270 et seq. of the Income Tax Code 1992 (CIR 92). Annex III of the implementing royal decree publishes the monthly schedules every year.
SPF Finances updates these schedules in December for the following tax year. Amounts are indexed to the health index.
2. Monthly schedule structure
For each family situation (single, married with one income, married with two incomes, legal cohabitant), the schedule contains a series of monthly taxable-salary brackets.
Each bracket associates a base lump-sum withholding to the lower bound and a marginal rate applied to the portion of salary above that bound.
Simplified example for a single person: between €1,180 and €2,250 monthly taxable, base withholding is €0 and marginal rate is 26.75%.
3. Four recognized family situations
Single: unmarried, divorced or widowed without partner. Standard schedule.
Married / legal cohabitant with one income: the other partner has no professional income (or < 10% of the total). More favorable schedule (partial spousal quotient).
Married / legal cohabitant with two incomes: each partner is taxed on their own income. Standard schedule per partner.
Assimilated legal cohabitant: since 2004, the legal cohabitant is fiscally treated as a married spouse, with the same options.
4. Reductions for dependents
The bracket-based withholding is then reduced by monthly lump-sum reductions: a progressive lump sum per dependent child (the more children, the higher the lump sum per child), a lump sum per other dependent, and additional lump sums if the worker or spouse is recognized as disabled.
A dependent child recognized as disabled counts double in the lump sum. Other dependents are typically ascendants or siblings sharing the household.
5. Reconciliation at the tax return
The professional withholding tax is only an advance on the final income tax. At the annual tax return, the actual tax is computed on total income, real or lump-sum professional expenses, and tax credits (pension savings, donations, etc.). If the withholding exceeds the tax due, the administration refunds the difference.
Conversely, in case of under-taxation (multiple employers, replacement income), a supplement may be claimed.