Job ads sometimes use the two loosely, but they differ enormously in how much certainty you get over income and schedule. Below: what a zero-hours contract is, which rules apply and why fixed hours work better for most working students.
What exactly is a zero-hours contract?
With a zero-hours contract no number of hours is agreed: you go to work when your employer calls you in. The employer only pays wages for the hours you work, but that arrangement must be on paper and, according to the Dutch government, only applies to the first 6 months. After that, if you're called in but can't work due to a cause at the employer's risk, or if you're not called in, you're entitled to continued pay; a collective agreement can extend that 6-month period under conditions. For each call-in you're entitled to at least 3 hours' pay [1]. It's a fixed-term or permanent contract without an agreement on the number of hours [1].
So what's the difference with a working-student contract?
A good working-student contract runs on a fixed number of hours a week, or at least a clear range, instead of loose call-ins. Then you know in advance what you'll earn and when you're expected, with room to adjust that temporarily around exams by mutual agreement.
Does an employer have to give notice before calling you in?
Yes. The employer must call you in at least 4 calendar days in advance, in writing or electronically; if you're called later, you're not obliged to come. If the employer cancels the call-in within those 4 days or changes the working times, you're entitled to pay for the hours you were called in for. A collective agreement can shorten the notice period to at least 1 day [1]. What that rule doesn't fix: you still only know shortly in advance whether, and how much, you'll work.
Do you eventually get a right to fixed hours on an on-call contract?
Yes. An employer may have you work as an on-call worker for at most one year. If you stay employed after that, you're entitled to a fixed number of hours, at least the hours per month you worked on average over the past 12 months; the employer must make that offer within a month after that year. You may refuse the offer, but the employer must then make it again every 12 months [1]. That's a useful backstop, but it does mean bridging a year of uncertainty.
Why doesn't a zero-hours contract suit most working-student roles?
- No income certainty makes it hard to combine with study costs and rent
- No fixed schedule makes it hard to plan work structurally around lectures and exams
- Structural, recurring work fits fixed hours better than loose call-ins
Why VOIDS works with fixed hours
VOIDS places working-student roles with a fixed number of hours a week; typically 4 to 24 hours. Uncertainty over income and schedule isn't part of a working-student role.
What changes on 1 January 2028?
On 7 July 2026 the Senate approved the Act on more security for flexible workers. According to the Dutch government the main provisions take effect on 1 January 2028. On-call contracts will then be replaced by a bandwidth contract with a minimum and maximum number of hours, where the difference is at most 30%; employees can refuse calls above the maximum. There is an exception for side jobs of people whose main activity is something else, such as people receiving state pension, pupils and students [2]. Position as of 11 October 2026.
Sources
- Rijksoverheid: Welke contracten zijn er voor oproepkrachten?, accessed 11 October 2026.
- Rijksoverheid (2026): Meer zekerheid voor mensen met een flexcontract, accessed 11 October 2026.
Transparency: VOIDS connects working students with organisations and therefore has an interest in this topic. We back up facts with sources and connect research and trends to our own experience from practice.
