Voluntary overtime: rules for relance hours and 120 hours

Friday afternoon. Your biggest client calls with a rush order. Your team is already running at full speed, but you need two more weeks to hit that deadline. Your staff are happy to put in extra hours, but you want to do it properly. No hassle with the labour inspection afterwards, no surprises on the payslip.

Voluntary overtime was designed for exactly these situations. But the rules? They've changed several times over the past few years. Relance hours (recovery overtime), 120 hours, 360 hours from April 2026. It's not always easy to see the wood for the trees.

In this article, we lay it all out clearly. What exactly is voluntary overtime, how does it differ from regular overtime, what tax benefits apply, and what changes in 2026? No jargon where we can avoid it. With concrete examples where we can.

What exactly is voluntary overtime?

Voluntary overtime is extra hours an employee works on top of their normal working week, on their own initiative and with a written agreement. It was introduced in 2017 through the Workable and Agile Work Act, with the aim of giving employers and employees more flexibility.

The key word here is "voluntary". Unlike classic overtime, where the employer asks the employee to stay longer, here the employee chooses it themselves. No one can be forced to work voluntary overtime. Makes sense, right? Yet in practice we see that this distinction isn't always drawn as sharply as it should be.

At Recruit, we guide employers who work with this scheme every day. What we notice time and again: the basic rule is simple, but as soon as you deal with different Joint Committees, or the legislation changes again, it gets more complex than you'd expect.

Voluntary vs. regular overtime: the difference

This is where it gets a bit legal. Not boring-legal, but it matters, because the difference between regular and voluntary overtime hits your wallet directly.

Regular overtime arises when an employee works more than the statutory working time (usually 38 hours per week) because of an exceptional increase in workload or an unforeseen necessity. The employer requests or requires it. And that brings two obligations:

• You pay an overtime premium (a 50% supplement on weekdays, 100% on Sundays and public holidays)
• You grant compensatory rest to respect the average working time

Voluntary overtime works fundamentally differently. The employee chooses it, and in return:

• No compensatory rest required
• For the relance hours (the first 240 hours from April 2026): no overtime premium, no NSSO contributions, no taxes
• Gross is literally equal to net

That last point is what gets many employers and employees excited. But there's a nuance we'll come back to later.

Want a full overview of how overtime is compensated in Belgium? Read our article on overtime pay in Belgium.

The quota: how many hours are allowed?

Here's the key point. And the numbers have changed quite a bit over the past few years.

The basic rule (statutory quota): An employee may work a maximum of 100 voluntary overtime hours per calendar year. That's the absolute minimum the law provides.

Increase via sector CLA: A sector-level collective labour agreement (CLA) can raise this to a maximum of 360 hours per year. Not every sector does this, so you always need to check what has been agreed in your Joint Committee. For more on how Joint Committees work and why they matter, see our article on Joint Committees in Belgium.

Relance hours (temporary scheme until end of 2025): On top of the statutory quota, employees could work up to 120 extra voluntary overtime hours, the so-called relance hours. These were introduced during the coronavirus crisis and extended several times. The special part? They applied in all sectors, whether or not a sector CLA existed.

Transition period (1 January to 31 March 2026): The scheme of 220 voluntary overtime hours (100 basic + 120 relance) is extended until 31 March 2026.

New permanent scheme (from 1 April 2026): And here's where it gets interesting. The federal government has approved a bill that makes the system permanent and sharply increases the quota:

• 360 voluntary overtime hours per year for most sectors
• 450 voluntary overtime hours in the hospitality sector
• Of which 240 hours fully net (no NSSO, no taxes, no overtime premium)
• The remaining 120 hours with a tax benefit through reduced professional withholding tax

That's a substantial increase. But note: the bill still has to be finally approved. In our experience with thousands of temporary workers, we see that employers who prepare early for new regulations have far fewer headaches later on.

The written agreement: how to set it up

No written agreement, no voluntary overtime. It's that simple.

The employee must agree in advance and explicitly to working voluntary overtime. You do this through a written agreement. A verbal arrangement isn't enough, even if your employee has worked for you for ten years and "everyone knows everyone".

The ground rules for the agreement:

• The agreement is valid for a maximum of six months
• It can be renewed after that period, each time for a maximum of six months
• It must be concluded before the start of the period in which the overtime is worked
• The employee may refuse to renew the agreement at any time, without consequences

Let's step back for a moment: why the six-month limit? The legislator wants to avoid employees signing long-running commitments under pressure. The limited duration lets the employee reassess every six months whether the extra hours are still feasible and desirable.

In practice, you'll see many employers include this agreement as an annex to the employment contract. That's fine, as long as the document clearly states that it specifically concerns voluntary overtime, names the maximum period, and is signed by both parties.

You can sort this out and draft it yourself, or you can have Recruit handle the contract administration. We make sure the agreement meets all legal requirements and is linked to the correct pay.

The tax benefit: gross = net (but not always)

Let's be honest here. The tax benefit of voluntary overtime is attractive, but it doesn't work the same way for every hour. Let's not beat around the bush.

The relance hours (240 hours from April 2026):

• Fully exempt from NSSO contributions
• Exempt from professional withholding tax and personal income tax
• No overtime premium due
• Gross = net

In concrete terms: if your employee earns 20 euros an hour, they actually receive 20 euros net for each overtime hour. No social contributions taken off, no taxes. That's particularly advantageous for both employer and employee.

The other voluntary overtime hours (120 on top of the 240):

A different regime applies here. For these hours you do pay:

• The usual overtime supplement (50% on weekdays, 100% on Sundays and public holidays)
• But both employer and employee benefit from a tax reduction through the professional withholding tax

The honest truth? The net difference between regular overtime and voluntary overtime can sometimes work out against the employee. With regular overtime that carries a supplement, an employee proportionally keeps more per hour than with relance hours without a supplement, despite the tax benefit. It depends on the gross salary, the applicable bracket and the Joint Committee.

Want to calculate what your employees keep net? Our article on gross-to-net calculation walks you through it step by step.

Which sectors and employees qualify?

Not everyone can simply work voluntary overtime. A few important conditions apply.

Full-time employees: The scheme is primarily intended for full-time employees. They can work voluntary overtime without additional conditions (with a written agreement, of course).

Part-time employees: From April 2026, the rules become stricter for part-time employees who want to work voluntary overtime. They must:

• Have been employed part-time for at least three years with the same employer
• There must be a temporary increase in workload

That's an important restriction. In practice, it means you can't simply have a part-time employee who has just started work voluntary overtime.

Sector-specific maximums: The maximum quota can vary by sector. Hospitality (JC 302) gets an increased ceiling of 450 hours. In the construction sector (JC 124), specific rules apply. And in JC 200 (the supplementary national Joint Committee for white-collar workers), there are yet other arrangements.

After more than 15 years in Belgian payroll, we know exactly which rules apply per Joint Committee. Because let's be honest: the sector-specific exceptions are where most mistakes are made.

The internal limit: the 143-hour counter

Beyond the annual voluntary-overtime quota, there's an internal limit of 143 hours. This is a technical point many employers trip over.

The 143-hour counter tracks how many overtime hours (of all types combined) an employee has built up without compensatory rest yet being granted. Exceed that limit, and you first have to grant compensatory rest before you can have new overtime worked.

But here's the nuance: only part of the voluntary overtime counts towards that 143-hour counter. The first 25 voluntary overtime hours per calendar year don't count. The rest do.

Say your employee has worked 50 voluntary overtime hours. Then 25 count towards the internal limit (50 minus the first 25, which are exempt). Does that employee also have 100 regular overtime hours outstanding without compensatory rest? Then you're already at 125 of the 143 hours. So you have only limited room left.

Keeping track of these counters is an administrative chore. In our platform at Recruit, these calculations are tracked automatically, so you always know how much room is left.

Common mistakes with voluntary overtime

We regularly see companies fall into the same traps. Here are the five that come up most often.

1. No written agreement (or an expired one) The agreement lapses after six months. Forget to renew it, and the overtime worked afterwards is technically regular overtime, with all the consequences (overtime premium, compensatory rest) that entails.

2. Exceeding the quota without noticing Especially with employees who work for several employers, or who switch between regular and voluntary overtime, you quickly lose track.

3. Letting part-time employees join in without checking the conditions Stricter rules apply from April 2026. A part-time employee who has been employed for less than three years doesn't qualify.

4. Forgetting the 143-hour counter That internal limit applies to all overtime combined. Count only the voluntary overtime, and you may miss the full picture.

5. Confusing voluntary overtime with flexibility Voluntary overtime is no substitute for a good work schedule or staff scheduling. It's meant as a temporary tool, not a structural solution for understaffing.

What changes from 1 April 2026?

In short, for anyone who wants a quick overview:

For employers in most sectors:

• A maximum of 360 voluntary overtime hours per year (was 220 in the transition period)
• 240 of those fully net, without NSSO or taxes
• 120 of those with an overtime premium, but with a tax benefit through professional withholding tax
• Part-time employees: three years of seniority required, plus a temporary increase in workload

For the hospitality sector:

• A maximum of 450 voluntary overtime hours per year
• 360 of those fully net

What doesn't change:

• A written agreement remains mandatory (maximum six months, renewable)
• The 143-hour counter stays in place
• The voluntary nature remains essential: no employee can be forced

Want to know what these changes mean for your total wage cost? Check our guide on calculating wage costs in Belgium for a clear overview.

In short

Voluntary overtime gives employers and employees a flexible tool to absorb peaks. The scheme has been considerably expanded over the past few years, and with the permanent increase to 360 hours (450 in hospitality) from April 2026, it only becomes broader.

But flexibility demands correct administration. A written agreement renewed on time, a quota tracked precisely, and pay that matches the rules in force for each Joint Committee. Get it right and you gain a lot from it. Let it slide, and you risk disputes with the social inspection.

Belgian labour law around overtime isn't the simplest. But with the right information and the right tools, it doesn't have to give you a headache.

Frequently asked questions

Can my employee be forced to work voluntary overtime? No, absolutely not. The voluntary nature is essential. The employee must agree in advance and in writing. An employee who refuses to renew the agreement may not suffer any disadvantage for it.

Do voluntary overtime hours count towards the calculation of holiday pay and the end-of-year bonus? The net relance hours (the 240 hours without NSSO) don't count towards the calculation of social rights such as holiday pay. After all, they aren't subject to social security contributions. The other 120 voluntary overtime hours with an overtime premium generally do count, depending on your Joint Committee.

What if the quota runs out halfway through the year? Then the employee can't work any more voluntary overtime until the next calendar year. Extra hours on top of the quota are treated as regular overtime, with an overtime premium and compensatory rest.

Does the scheme also apply to temp workers? Yes, temp workers can work voluntary overtime too. The written agreement is then concluded between the temp worker and the temp agency (or the payroll partner). The quota is counted per calendar year, regardless of which user the hours are worked for.

As an employer, do I have to register voluntary overtime? Yes. You're required to keep an accurate record of all overtime worked, including voluntary overtime. If the social inspection carries out a check, you must be able to produce it.

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How Recruit helps you

Don't feel like puzzling over NSSO percentages and overtime yourself? We get it.

With Recruit:

• Contracts in under 60 seconds: create trial and temp contracts without hassle
• Automatic payroll calculation: correct pay in line with current legislation and your Joint Committee
• Dimona (immediate employment declaration) and social documents: we handle all declarations, you focus on your business
• 24/7 personal support: always a dedicated contact who knows your company
• No fixed monthly costs: pay only for what you use

Try Recruit or get in touch with our HR experts for tailored advice.

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The information in this article is purely informative and does not replace professional legal or accounting advice. Labour legislation changes regularly. The rules can differ by Joint Committee and sector. Always consult the current legislation or get in touch with an HR expert for advice tailored to your situation. The amounts and percentages in this article are based on the regulations known as of the publication date (February 2026).