Part-time contracts 2026: from the 1/3 rule to the 1/10 rule

Published on 12 October 2026

Since 1 June 2026 you can conclude part-time contracts that are far smaller than before. The Act of 18 May 2026 containing various labour provisions lowers the minimum weekly working time for part-time employees from one third to one tenth of a full-time position. For anyone working with short shifts — a two-hour cleaning round, a peak moment at the checkout, weekend support in a residential care centre — that changes the playing field.

But be careful: one rule changes, three others stay exactly where they were. And that is precisely where employers get it wrong.

What exactly changes

Until 31 May 2026, Article 11bis of the Employment Contracts Act of 3 July 1978 applied: the weekly working time of a part-time employee could not fall below one third of the weekly working time of a full-time colleague in the same category. Since 1 June 2026 that floor has been lowered to one tenth.

In figures, based on a full-time regime of 38 hours per week:

Old floor (1/3): 12 hours 40 minutes per week
New floor (1/10): 3 hours 48 minutes per week

Under a sectoral full-time regime of 37 hours — as in the cleaning sector — the floor drops from roughly 12 hours 20 to 3 hours 42 per week.

The option to derogate from that limit by Royal Decree for certain branches of activity or categories of employees remains in place. Conversely, your sector can keep a higher minimum through a collective labour agreement. So always check your joint committee first before drawing up a four-hour-a-week contract. You will find more background at the FPS Employment.

The 3-hour rule does still stand

This is the most common misconception of recent months. The reduction to one tenth concerns the weekly working time set out in the contract. It says nothing about the length of a single work period.

Article 21 of the Labour Act of 16 March 1971 remains unchanged: every work period must in principle last at least 3 hours. A work period is a continuous stretch of work that may be interrupted by an ordinary break (coffee, meal). Someone who works from 8 to 11 and again from 15 to 19 performs two periods that each comply with the rule.

In practice that means: a contract of 4 hours a week is possible, but you should preferably schedule those 4 hours in a single block — not as four separate one-hour stints.

Unless your sector has a derogation. Such derogations genuinely exist, through the Royal Decree of 18 June 1990 or through sectoral collective agreements. In classic cleaning (JC 121), for instance, a derogating arrangement has applied for some time, allowing a shorter period per site, provided the sites follow on directly from one another and the travel time in between counts as working time. An arrangement like that is sector-specific and tightly framed — do not simply copy it across to another joint committee.

What this means per sector

Retail. Short peak contracts for Saturday mornings or late-night shopping become legally simpler. A fixed weekend assistant on 5 hours a week no longer has to be a workaround. See also our sector page retail.

Cleaning and building services. This is where the tension was highest: many cleaning rounds last two to three hours and clients want them outside their office hours. The new floor creates more room, but the combination with the 3-hour rule and the sectoral agreements remains the real scheduling puzzle. Read how to tackle that at /cleaning.

Care and welfare. Small contracts for weekend support or night cover become easier to formalise. The rules on publishing variable part-time schedules continue to apply in full — we wrote about that earlier in publishing variable part-time work schedules in the care sector.

Hospitality. Alongside flexi-jobs and casual staff (extra's), you gain an extra instrument: a small but fixed part-time contract for someone who works every Friday evening. That offers more predictability than issuing a fresh day contract each time.

Four obligations that do not change

Written contract, at the latest at the start. Every part-time employment contract must be in writing, no later than the moment the employee starts. It states the agreed working arrangement (the number of hours per week) as well as the work schedule (which days, which hours, which breaks).
Publication of variable schedules. If you work with variable part-time schedules, you must in principle publish the individual schedule at least seven working days in advance. A sectoral collective agreement can shorten that period, but not below three working days. Your work rules must set out how and when you publish.
Record deviations. If the actual work performed deviates from the published schedule, that deviation must be recorded. Without correct registration you risk a rebuttable presumption of full-time employment — with all the consequences that entails for your NSSO settlement.
Dimona stays Dimona. A smaller contract does not mean less administration. Every hire still requires a declaration.

In addition, the same act relaxes the way work schedules must appear in the work rules: you can now set out a framework for ordinary working time that defines the time bands within which work takes place in your company. Full-time and fixed part-time schedules that fall within that framework no longer have to be listed one by one. That saves a lot of amendment procedures, but it does not release you from the duty to give employees their concrete schedule in good time.

Before you go smaller: three considerations

Check your joint committee. Sectoral collective agreements can provide for a higher floor or a different minimum period of work. What the law allows is not automatically allowed in your sector.
Think about the employee side. Very small contracts have consequences for your staff's income and their social security build-up. On top of that, anyone looking for more hours has priority for vacant hours in the same role. A proper conversation up front prevents turnover.
Calculate the real cost. Four short work periods cost more in coordination, briefing and travel than one block of twelve hours. Small contracts are flexible; they are not automatically cheap.

From rule to roster

The difficult part of this reform is not the rule itself, but the combination: a contractual weekly duration, a minimum duration per work period, a publication deadline and a sectoral exception — all at the same time, for dozens of staff members.

That is exactly where software makes the difference. In Forganiser you set the contractual weekly duration per employee and immediately see whether a scheduled shift falls within the rules. Contract data, schedules and hours worked sit in the same file, so your HR administration and Dimona declarations automatically keep pace with your planning. For short-term and variable employment you will find more explanation at flexible work.

Want to know what you may actually change in an existing schedule? Then also read changing a work schedule: what does Belgian law say?.

In short: on 1 June 2026 the floor for part-time contracts dropped from one third to one tenth of a full-time job. The 3-hour rule per work period, the written contract requirement and the publication deadlines remain. Combine both correctly and you gain real flexibility. Forget one of them and you pay the difference at the first inspection.