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What if I switch to four-fifths? What you really lose in net pay in 2026

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Calculate your net pay at four-fifths

At four-fifths, a single white-collar worker on €3,000 gross works 20% less, but their net pay falls by only 13.8%: €2,261.33 full-time, €1,949.62 at four-fifths, i.e. €311.71 less a month. With the NEO parental leave allowance on a one-fifth reduction (€179.60 gross as of 1 March 2026, about €183.19 since the September indexation), the loss drops to €159.94, 7.1% of their net pay.

Withholding tax (bedrijfsvoorheffing / précompte professionnel) falls faster than gross pay, and the work bonus is recalculated on the full-time equivalent. Calculate your case: salary, option, parental leave or time credit.

Calculate your net pay at four-fifths

Enter your full-time salary, the new working time and the framework: a simple agreement with the employer, parental leave or time credit. Nothing is sent: everything is calculated in your browser.

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13.8%less net pay at four-fifths on €3,000 gross, for 20% less working time
€72a month: the price of a day off a week, with no allowance
€152more net a month with parental leave on a one-fifth reduction (estimate since September 2026)

Why net pay falls less than working time

At four-fifths, your gross pay falls by 20%. Your net pay falls less, for three reasons.

  • Withholding tax is progressive. The euros you no longer earn were taxed at your highest rate, often 42.8% or more. So withholding tax falls more than gross pay.
  • The work bonus is recalculated on the full-time equivalent. For a modest salary, it increases part-time: you pay fewer social security contributions.
  • The special social security contribution depends on the month’s gross pay: it falls too.
Working time80%
Net kept, with no allowance86.2%
Net kept with parental leave92.9%
Single white-collar worker, €3,000 gross full-time, switching to four-fifths. The figures are given in the table below.
Full-time grossNet full-timeNet at four-fifthsDifferenceNet lostWith parental leave
€2,500€2,175.62€1,886.98− €288.6413.3%6.3%
€3,000€2,261.33€1,949.62− €311.7113.8%7.1%
€3,500€2,400.40€2,064.22− €336.1814%7.7%
€4,000€2,614.26€2,258.72− €355.5413.6%7.8%
€5,000€3,051.72€2,614.26− €437.4614.3%9.4%
€6,000€3,467.07€2,963.78− €503.2914.5%10.1%
Single white-collar worker, no children. Monthly net calculated by the Indexo engine, parameters as of 1 October 2026. Last column: with the parental leave allowance on a one-fifth reduction (€183.19 gross, after NEO withholding tax).

For other profiles, the net lost ranges from 13% to 20% for 20% less working time. It is highest when tax is already very low, for example for a single-income couple on a modest income: there is then little withholding tax left to save.

Full-time grossSingle blue-collar workerWhite-collar worker, single-income couple
€2,50013.5%19.5%
€3,00013.8%17.4%
€3,50014%13.6%
€4,00013.5%13.9%
€5,00014.4%14.5%
€6,00014.7%13.5%
Share of net pay lost by switching to four-fifths, with no allowance. Blue-collar worker: contributions on 108% of gross pay. Single-income couple: the partner has no earned income.

With or without an NEO allowance

Reducing your working time by mutual agreement with the employer gives no right to an allowance. The National Employment Office (NEO) pays a flat-rate allowance in only two frameworks: parental leave or time credit, with a reason or at the end of a career. Its amount does not depend on your salary.

OptionGross as of 1 March 2026Estimated gross since September 2026Withholding taxEstimated net
Parental leave, one-fifth reduction€179.60€183.1917.15%€151.77
Parental leave, half-time€529.42€540.0117.15%€447.40
End-of-career time credit, one-fifth reduction, single€361.39€368.6217.15%€305.40
End-of-career time credit, one-fifth reduction, cohabitant€299.47€305.4635%€198.55
End-of-career time credit, half-time€644.72€657.6117.15% or 35%depending on the situation
Time credit with a reason (care, training)to be confirmedto be confirmeddepending on the situationamount in your decision
Monthly NEO allowances for a worker who reduces their working time, starting from full time. September 2026: Indexo estimate (+ 2% indexation). Withholding tax is deducted by the NEO.

NEO amounts as of 1 March 2026, then indexed by 2% in September 2026: the exact September amounts are to be confirmed on the NEO website.

Example: a 60-year-old cohabiting white-collar worker earning €3,500 gross who takes end-of-career time credit on a one-fifth reduction receives €2,262.77 net a month, salary and allowance combined, instead of €2,400.40. They lose 5.7% of their net pay.

And half-time?

Half-time, the effect is even stronger: a single white-collar worker on €3,000 gross keeps 60.1% of their net pay while working half as much, and 79.9% with half-time parental leave.

Full-time grossNet half-timeNet lostWith parental leaveNet lost with the allowance
€2,500€1,209.4844.4%€1,656.8823.8%
€3,000€1,359.2239.9%€1,806.6220.1%
€3,500€1,485.4138.1%€1,932.8119.5%
€4,000€1,655.5336.7%€2,102.9319.6%
€5,000€1,918.3537.1%€2,365.7522.5%
€6,000€2,161.4737.7%€2,608.8724.8%
Single white-collar worker, no children. Half-time parental leave: €540.01 gross estimated since September 2026, withholding tax of 17.15%.

What also changes: holiday pay, pension, illness

  • Holiday pay is calculated on your work in the previous year. After a full year at four-fifths, the net double holiday pay of a white-collar worker on €3,000 gross falls from about €1,471 to €1,275. Days of time credit do not count towards holidays.
  • Pension: parental leave or time credit with an allowance is in principle an assimilated period (treated as worked), calculated on a notional salary. Without an allowance, your pension is calculated on the salary actually earned. The pension reform under discussion in 2026 could limit these assimilated periods: check your career on MyPension.
  • If you fall ill during part-time time credit, your benefits are reduced pro rata. During a full break, you are not entitled to them.

Are you in a couple? The couple’s budget compares which of you would lose least by reducing working time.

Frequently asked questions

How much do you really lose by switching to four-fifths?

For a single white-collar worker, between 13% and 15% of net pay depending on salary, for 20% less working time. At €3,000 gross: €311.71 a month, 13.8% of their net pay. With a parental leave or time credit allowance, the loss is even smaller.

Does working four-fifths give entitlement to an NEO allowance?

Only as part of parental leave (child under 12, 20 months on a one-fifth reduction) or time credit with a reason or at the end of a career. A part-time arrangement freely agreed with the employer gives no right to an allowance.

Why does my work bonus increase at four-fifths?

It is calculated on your salary converted to full time, then reduced to your working time. If your full-time gross pay is modest, the bonus weighs more in a reduced salary: your social security contributions fall more than proportionally.

Does working four-fifths reduce my pension?

With parental leave or time credit paid by the NEO, the period is in principle assimilated (treated as worked): it counts for the pension on the basis of a notional salary. Without an allowance, the pension is calculated on the salary actually earned, so slightly lower. The 2026 draft pension reform could limit assimilated periods.

Will my holiday pay fall?

Yes, the following year: it is calculated on work in the previous year. After a full year at four-fifths, expect about 20% less. Days of time credit are not treated as worked for holidays.

What next?

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.