Belgium Notice Period Calculator: Opzegtermijn / Preavis Explained (2026)

If your contract started between 1 January 2014 and 31 May 2026, you can go straight to the table or the calculator below; a contract that started earlier, or that starts from June 2026 onward, needs the regime sections first.

Ask a Belgian search engine "opzegtermijn berekenen" and it often hands back a single table, as though one number could answer the question, but a Belgian notice period is a lookup inside one of four different regimes, decided by the date your employment contract started, not by today's date.

A contract that began in 2011 is measured on a different scale than one that began in 2021, and from the summer of 2026 a contract beginning in June reads slightly differently than one beginning in August. For anyone hired before 2014, the answer is not even one lookup but two calculations added together. Belgian legal practice calls this the opzegtermijn in Dutch and the préavis in French, both names for the same set of rules.

This page works through all four regimes, gives you the full scale with its anchor points, and hosts a calculator that does the lookup once you tell it when your contract began.

Information last verified on 21 July 2026. This page provides general legal information and does not constitute legal advice in an individual case.

Protected categories: the general rules above may not apply to you

The scale and figures described on this page are the general rules for a typical dismissal or resignation. They do not apply as described to a worker who falls into one of the protected categories below. Each carries its own fixed indemnity, and in some cases its own procedure, in place of the general rules.

• Pregnant workers. Under article 40 of the arbeidswet van 16 maart 1971, protection runs from the moment the employer is informed of the pregnancy until one month after the end of the postnatal rest period. An unjustified dismissal within that window carries a fixed indemnity of six months' gross pay.
• Union delegates and candidates in social elections. Under the wet van 19 maart 1991, the fixed indemnity is set by seniority: two years' pay under 10 years of seniority, three years' pay from 10 to under 20 years, and four years' pay from 20 years onward. Where reinstatement is requested and refused within 30 days, the employer owes that amount plus wages for the remaining time until the end of the electoral mandate.
• Prevention advisers. Under article 10 of the wet van 20 december 2002, the indemnity is two years' pay under 15 years of service as prevention adviser, and three years' pay from 15 years onward. A special procedure applies before any dismissal: the employer must notify the adviser and seek the prior agreement of the CPBW / CPPT committee, and where that agreement is refused or not given in time, the employer must obtain the labour inspector's advice before proceeding.
• Time credit (tijdskrediet). Under article 21 of CAO nr. 103, protection starts three months before the requested start date where the employer has more than 20 staff, or six months before where it has 20 or fewer, and ends three months after the credit period ends. A violation carries an indemnity of six months' pay.
• Thematic leave (parental leave, leave for medical assistance, palliative care leave). This rests on a separate instrument from time credit above: under article 101 of the herstelwet van 22 januari 1985, protection runs from the day the leave is agreed or requested until three months after it ends. A violation carries an indemnity of six months' gross pay.

These protection indemnities do not stack with each other or with ordinary severance. Where a protected category applies, its own indemnity replaces the general rule described above rather than adding to it.

Enter which side of the notice you are calculating, given by an employer or your own resignation, the date your contract began, and the date notice was given. The calculator identifies which of the four regimes applies from the start date and returns the notice in weeks. For a contract before 2014, it also asks whether you are a bediende or an arbeider, and for a bediende, whether gross annual pay on 31 December 2013 was above the 32,254 euro threshold, because that decides how the frozen part of your notice is worked out.

How the scale works

The scale below is article 37/2 paragraph 1 of the wet van 3 juli 1978, applied since 1 January 2014 to notice given by an employer, identical for a bediende and an arbeider since the eenheidsstatuut reform. It reads as seniority bands, "from X to less than Y", each attached to a number of weeks.

Three anchors are worth remembering: 5 years of seniority produces 18 weeks, 10 years produces 33 weeks, and 20 years produces 62 weeks.

The four regimes, and which one is yours

Contracts that started before 1 January 2014

Not read off this table at all. A two-part calculation under two bodies of law, covered in full below.

Contracts that started from 1 January 2014 to 31 May 2026

The scale above, applied without a ceiling, all the way up through 23 years and beyond at one additional week per further year.

Contracts that started from 1 June 2026 to 31 July 2026

The wet van 18 mei 2026 inserted article 37/2 paragraph 1/1, capping employer notice at 52 weeks once seniority reaches 17 years. Below 17 years the scale above is unchanged; from 17 years on, notice holds at 52 weeks instead of continuing to 54, 57, 60, 62 weeks and beyond. The cap reaches only contracts starting from 1 June 2026 onward. A contract already running on that date keeps accruing on the uncapped scale, permanently.

Contracts that start from 1 August 2026 onward

The wet van 3 juni 2026 (NUMAC 2026201577) layers a second change on top of the first. For contracts starting from 1 August 2026, the graduated first-six-months steps, 1 week, then 3, then 4, then 5 weeks, are replaced with a flat 1 week for the entire first six months. This is not an employer-only change: it rewrites all three scales in article 37/2 at once, the employer's notice in paragraph 1, the employee's resignation notice in paragraph 2, and the tegenopzeg in paragraph 3. A contract starting from 1 August 2026 carries both 2026 reforms together.

If your contract started before 2014

For a contract that began before 1 January 2014, the transitional cliquet under articles 67 to 69 of the wet van 26 december 2013 applies. Notice is Part 1 plus Part 2, added together.

Part 2 is seniority counted from 1 January 2014 onward, counter reset to zero, run through the same scale used for post-2014 contracts above.

Part 1 splits three ways, by status and pay on 31 December 2013.

A lower-paid bediende, gross annual salary on 31 December 2013 of 32,254 euro or less, has Part 1 at 3 months per started 5-year period of pre-2014 seniority. A started period counts in full, so 6 years is two started periods, giving 6 months.

A higher-paid bediende, pay above that threshold, has a different Part 1: one month per started year, minimum three months. This is the statutory default under article 68 as amended, in force since 28 October 2023, unless a valid notice clause already existed in the contract on 31 December 2013, in which case that clause governs instead. The older "Claeys formula", a court-built proxy for a "reasonable term" used between 2014 and 27 October 2023, is legacy doctrine relevant only to dismissals decided in that earlier window, not the rule for a dismissal calculated today.

For an arbeider, Part 1 comes from the sectoral collective agreement of the paritair comité covering the employer on 31 December 2013, and it cannot be reduced to a single number here: it depends on the sector. Check the agreement for your paritair comité, or use the calculator above, which refuses to guess and flags the result as incomplete.

Because an arbeider's pre-2014 Part 1 is typically worse than the 2014 scale would produce, the RVA / ONEM runs a state-funded top-up, the ontslagcompensatievergoeding, for arbeiders hired before 1 January 2014 dismissed with sufficient seniority. It supplements notice or indemnity actually paid up toward what the post-2014 scale would have produced, paid by the RVA rather than the employer, and claimed on form C4.

Notice given by the employee

If you are resigning, a shorter scale applies, regardless of when your contract started.

Notice given by an employee never exceeds 13 weeks, however long the seniority. For contracts starting from 1 August 2026, the sub-6-month band here also collapses to a flat 1 week.

A related mechanism is the tegenopzeg, or contre-préavis, under article 37/2 paragraph 3. Finding a new job while working out an employer's notice shortens the remaining obligation: 1 week under 3 months of seniority, 2 weeks for 3 to 6 months, 3 weeks for 6 months to 1 year, 4 weeks for 1 year or more. From 1 August 2026 the sub-6-month tier also flattens, to 1, 3 and 4 weeks.

When notice starts and how it must be given

Notice does not start the day it is given. It starts on the Monday following the calendar week in which notice was given, not simply the next day. Notice handed over on a Tuesday only begins to run the following Monday.

How notice may be given is asymmetric. An employee may hand over a signed document, send a registered letter (effective the third working day after posting), or use a bailiff's writ. An employer has fewer options, only a registered letter or a bailiff's writ, on pain of nullity; simply handing over a letter, which works for a resignation, is not valid for an employer's notice.

If an employer's notice is given in the wrong form, the notice itself is null, but the dismissal still stands: the relationship ends immediately, on the date the employer intended. What changes is the consequence, a null notice converts the employer's obligation into an indemnity covering the notice period, rather than an employee working out a valid notice. A dispute over whether notice was validly given, or what indemnity is owed instead, is heard by the arbeidsrechtbank, the tribunal du travail in French.

Job-hunting leave during your notice

During a notice period, either side, paid time off for job hunting is available. This is the sollicitatieverlof, congé de sollicitation in French, and the amount depends on outplacement.

With outplacement, the leave is 1 day, or two half-days, per week for the whole notice period.

Without outplacement the answer turns on how long your notice is, and this is where most summaries go wrong. If your total notice period is 26 weeks or less, you get a full day, or two half-days, per week for the entire period. That covers most dismissed employees, since on the scale above notice only passes 26 weeks at around eight to nine years of seniority. Only where the notice period runs longer than 26 weeks does it start at half a day per week and rise to a full day for the final 26 weeks.

Part-time work reduces this leave proportionally.

What sits above the statutory scale

Everything above is the federal floor set by the wet van 3 juli 1978, not necessarily the whole answer for any individual worker.

Belgian employment is organised into sectors, each with a paritair comité, a commission paritaire in French, a joint body of employer and union representatives. These committees negotiate collective agreements, the CAO or CCT, and when made generally binding by Royal Decree, a mechanism called algemeen verbindend verklaring, the agreement binds every employer within the committee's scope. A sectoral CCT can set a longer notice than the statutory scale, and in several sectors it does. The paritair comité number often appears on a payslip in practice, and an individual committee can impose its own extra payslip requirements, but the mandatory payslip content list set by the KB van 27 september 1966 does not itself require it. Where the paritair comité covering an employer is not already known, the official lookup tool at public-search.werk.belgie.be allows a search by a committee number or name already known, or browsing the full list; it is not a wizard that identifies a committee from a description of the work performed. Where the committee genuinely cannot be identified this way, the official route is a written advisory request to the Labour Law Inspection, which takes at least four months and produces non-binding advice, since only the labour courts can settle the question definitively.

Separately, workers with at least 6 months of seniority who are dismissed may have a claim under CAO nr. 109, on manifestly unreasonable dismissal (kennelijk onredelijk ontslag): where a dismissal rests on no connection to conduct or suitability and no operational necessity, a judge can award 3 to 17 weeks' pay on top of notice or severance. This excludes temp-agency workers, student contracts, dismissals tied to statutory pension age, and collective dismissals. Collective dismissals follow a separate information-and-consultation procedure under the Wet van 13 februari 1998 (known as the Wet Renault), with the step-by-step procedure set by CAO nr. 24, rather than the individual rules described on this page.

The deadline that ends every claim

Article 15 of the wet van 3 juli 1978 time-bars claims arising from an employment contract at the earlier of two points: one year after the contract ends, or five years after the fact giving rise to the claim, whichever comes first. The five-year branch is itself capped so that it can never run past one year after the contract ends. The scope is broad, covering actions arising from the contract in general, which includes both a claim for unpaid severance and a challenge to a dismissal.

Where severance is paid in instalments under article 39bis, a separate sub-rule applies: the one-year period runs from the last monthly instalment actually paid by the employer, not from the date the contract ended.

This deadline does not pause while a claim is negotiated informally, and it does not pause while a dispute with the RVA / ONEM is working its way to a resolution.

This page provides general legal information about Belgian notice periods and does not constitute legal advice for an individual case. Notice calculations depend on precise dates, your status, sector, and any applicable collective agreement, and the rules changed twice in 2026. Confirm your own figure against the current text on ejustice.just.fgov.be or werk.belgie.be, or consult an advocaat, before relying on it.