Employees · Calculate and check
Why has my net salary changed? The causes in 2026
Updated on
Since 1 November 2026, withholding tax on pay has been calculated differently (Royal Decree of 27 September 2026). The calculations on this page still follow the previous rules: for pay received from 1 November, withholding tax and net pay may differ. Update in progress.
Net pay changes for six reasons: gross pay (indexation, pay rise, bonus), the work bonus, which falls as gross pay rises, the children and couple situation declared to the employer, the withholding tax (bedrijfsvoorheffing / précompte professionnel) scale (new on 1 January), the number of days worked (meal vouchers, commuting) and absences. Example: with the 2.21% indexation of January 2026, a single white-collar worker goes from €3,000 to €3,066.30 gross. Their net pay only rises by €15.83, because their work bonus falls by €18.16 (Indexo calculation, 2026 scale).
Compare two payslips
Copy the gross and net pay from two payslips (and the deductions, if you have them), or drop in the two PDFs. Indexo separates the effect of gross pay, the effect of your situation and what remains to be explained. Nothing is sent.
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What changed in 2026, month by month
If your two payslips fall either side of one of these dates, part of the difference comes from the rule change, not from a mistake.
| Date | Change | Effect on your payslip | Source |
|---|---|---|---|
| 1 January 2026 | New withholding tax scale | Lower for most employees: for example €17 more net a month on €2,800 gross (married, no children), €23.80 on €4,000 gross (married, one child) | Securex |
| 1 January 2026 | 2.21% indexation of JC 200 salaries | Gross pay rises by 2.21%; net pay, slightly less | Securex |
| 1 January 2026 | Train season ticket reimbursed at 100% in JC 200 | The commuting allowance increases | Partena Professional |
| 1 August 2026 | Fiscal work bonus at 63% of part B (instead of 52.54%) | Slightly less withholding tax for modest salaries | Partena Professional |
| 1 September 2026 | New work bonus amounts | Slightly different contributions for modest salaries | NSSO |
| 1 September 2026 | Telework allowance raised to up to €164.21 a month | If your employer follows the ceiling, net pay rises | Securex |
| 1 January 2027 | JC 200 indexation: 4.32% expected (forecast, not yet official) | Gross pay rises; the exact figure will be known in early January | Acerta (forecast) |
| 1 January 2027 | New withholding tax and work bonus scales | Not yet published | — |
The full list of changes on 1 January 2027 is on the ‘What’s changing’ page; your sector’s indexation, on ‘Salary indexation’.
When gross pay rises, net pay rises less
Every extra euro of gross pay bears contributions and withholding tax. For modest salaries, it also reduces the work bonus: that is why an indexation or a small pay rise barely shows in net pay.
| Gross per month | Net | Extra net for €100 gross | Share kept |
|---|---|---|---|
| €2,000 | €1,962.14 | €59.55 | 60% |
| €2,500 | €2,175.62 | €16.19 | 16% |
| €3,000 | €2,261.33 | €23.89 | 24% |
| €3,500 | €2,400.40 | €43.97 | 44% |
| €4,000 | €2,614.26 | €41.70 | 42% |
| €5,000 | €3,051.72 | €43.98 | 44% |
The full shape of this curve is on ‘Your net pay curve’.
The causes, one by one
Indexation
Most sectors index wages once a year, often in January; others follow the pivot index. In joint committee 200, the largest for white-collar workers, salaries rose by 2.21% on 1 January 2026. For January 2027, the forecast is 4.32% (Acerta): the official figure will be known in early January.
A pay rise, a bonus or extra hours
They are added to the month’s gross pay. A bonus paid separately, such as double holiday pay or the year-end bonus, is subject to withholding tax on non-recurring pay: you keep less of it than of your salary. The following month, net pay goes back to normal.
The work bonus
It reduces contributions on modest salaries: up to €299.53 a month full-time, nothing above €3,403.62 gross (white-collar workers). When your gross pay rises, it falls. Its amounts were adjusted on 1 September 2026.
Your dependants
A dependent child declared to your employer reduces withholding tax by €52 a month, two children by €138, three by €367. A single white-collar worker on €3,000 gross thus goes from €2,261.33 to €2,313.33 net with one child. If a child has been born and your net pay has not changed, your employer probably does not know yet.
Marriage or legal cohabitation
With a spouse with no income, the marital quotient allocates part of your salary to your spouse: withholding tax falls noticeably. With a working spouse, withholding tax changes little, but the special contribution follows the couples’ scale.
The number of days worked
Your share of meal vouchers (€1.09 per voucher) and often the commuting allowance depend on the days worked. A 22-day month and a 19-day month therefore do not give the same net pay, for the same gross.
An absence, illness, temporary unemployment
After the guaranteed wage period, your health insurance fund pays sickness benefits: your payslip drops, or even disappears. Temporary unemployment is paid by your payment body. Starting or leaving during the month also gives a shorter payslip.
Working time
Switching to four-fifths reduces gross pay by a fifth, but net pay by less than a fifth: withholding tax falls faster and the work bonus increases. Simulate it with ‘Switching to four-fifths or half-time’.
Frequently asked questions
My gross pay went up but my net pay barely did. Is that normal?
Yes, for a modest salary. Every extra euro of gross pay bears 13.07% in contributions plus withholding tax, and reduces the work bonus. On €3,000 gross, the 2.21% indexation of January 2026 only brought a single white-collar worker €15.83 net, because their bonus fell by €18.16.
Why is my January net pay different from December’s?
In January, three things often change at once: indexation in many sectors, the new withholding tax scale and the end of December bonuses (year-end bonus). Compare your January payslip with November’s rather than December’s.
My net pay fell although my gross pay did not change. Why?
The most common causes: fewer days worked (meal voucher share, commuting), a child who is no longer a dependant, a changed family situation recorded by your employer, or the correction of a past error. Copy your two payslips into the tool: the difference that comes neither from gross pay nor from your situation is isolated.
Will withholding tax change on 1 January 2027?
Probably: the scale is adjusted every year. The 2027 scale has not yet been published as of 1 October 2026. Indexo will include it as soon as it is published, normally at the end of December.
What next?
- Check my payslipEvery line of a payslip, recalculated and explained.
- Salary indexationYour sector’s next indexation and its effect in net pay.
- What’s changingAll the changes on 1 January 2027.
- Your net pay curveWhat is left of every extra euro of gross pay.
Sources
Parameters in force on 1 October 2026. Each parameter links to its source, the official one where it exists; a secondary source is flagged as such.
- Nouvelles règles en matière de précompte professionnel pour 2026 (29 December 2025), Securex (secondary source).
- L’index 2026 dans la commission paritaire 200 est connu : 2,21 %, Securex (secondary source). Cross-checked with: Adecco, Salaires CP 200 : augmentation de 2,21 % à partir du 1er janvier 2026.
- Modification de l’annexe III de l’AR/CIR 92 : nouvelles règles pour le précompte professionnel (3 August 2026), Partena Professional (secondary source). Cross-checked with: Forum for the Future, Avis aux débiteurs du précompte professionnel (3 August 2026).
- Instructions administratives : le bonus à l’emploi, NSSO.
- L’indemnité de télétravail portée à 164,21 euros à partir du 1er septembre 2026, Securex (secondary source).
- JC 200 sector agreement: train reimbursed at 100% from 1 January 2026, bicycle allowance of €0.32 per km from 1 October 2026, Partena Professional (secondary source). Cross-checked with: the ACCG (ceiling of €36,688 for private transport in 2026) and the CGSLB/ACLVB.
- Les salaires augmentent en octobre dans neuf secteurs (29 September 2026); JC 200: 4.32% expected in January 2027, Acerta, via L’Avenir (secondary source). Cross-checked with: La DH, 7 October 2026.
- Calcul du précompte professionnel : annexe III de l’AR/CIR 92 et formule-clé 2026, FPS Finance.
- Meal vouchers: Royal Decree of 10 November 2025, maximum value of €10, Belgian Official Gazette. Cross-checked with: the CSC/ACV and Partena Professional.