There are employment contracts that begin with an implicit promise: "it's only for a few months." The problem is that, as time passes, the worker stays, the company relies on them, a routine sets in, and suddenly the question arises that determines stability, rights, and... compensationSo, does this contract have an end date or could it become an open-ended contract?

The indefinite term contract exists precisely for situations where a company needs to hire but cannot define an end date from the outset. However, “not knowing the date” does not mean “being able to use it always.” In Portugal, the indefinite term has its own rules, specific justifications, and limits. And when these rules are used incorrectly, the contract may be considered indefinite, with serious consequences.

In this article, we explain what an indefinite-term contract is, when it can be used, what clauses it should contain, what the worker's rights are, how expiration, notice periods, and compensation work, and the most common errors that lead to disputes.

Um contrato a termo incerto é um contrato que garante um pagamento futuro ao comprador, mas apenas se uma determinada condição for cumprida. Se a condição não for cumprida, o comprador não recebe nada.

The uncertain fixed-term contract is a fixed-term employment contract, but without a defined end date. Instead of ending on a specific day, it ends when a future and uncertain event occurs that justifies the hiring.

In practice, the company hires for a temporary need, but this need does not have a fixed end date. The end of the contract is linked to the end of the reason: for example, the return of a replaced employee, the completion of a project, the end of a construction, or the conclusion of a specific seasonal task.

The term is “uncertain” because the date is not known. But the basis must be clear, real, and verifiable. If the basis is vague or the need is not temporary, the contract loses protection.

Indefinite term contract vs fixed-term contract

The difference seems simple but has a huge impact.

In a fixed-term contract, there is an end date or a defined duration. The company knows when it ends, and the employee does too.

In an indefinite term contract, there is no end date. There is an event that ends the temporary need.

What does this change in real life:

• In managing worker expectations, because there is no “day X”.
• In the employer's legal management, because they have to prove the temporary need and the termination event.
• In expiry procedures, end-of-term communication gains particular importance.

If you want to understand the big picture of contracts, you can supplement with Types of employment contracts.

When is a contract for an indefinite term permitted?

The fixed-term contract for an uncertain period is not a “trick” to avoid permanent contracts. It can only be used when there is a duly substantiated temporary need.

The most typical scenarios, in practice, include:

• Covering for an absent worker when their return date is unknown (long-term illness, parental leave, secondment).
• Replacement of a departing worker with an uncertain departure date, for example, during a lengthy recruitment process.
• Execution of a temporary task or project without a fixed deadline, such as a construction job, system implementation, or specific campaign.
• Exceptional increase in activity when duration cannot be accurately predicted.

The decisive point is this: the reason must be temporary. If the function is permanent and the post is structural, the notion of an uncertain term is at risk.

The obligation to provide written reasons

Herein lies one of the most expensive errors.

In a contract for an indefinite term, the grounds must be written and concrete. “Company's needs” is not enough. “Increase in workload” without explaining what, why and in what context, is also weak.

A strong foundation should explain:

• What is the temporary requirement?;
• Why is it temporary?;
• the link between the worker's need and function;
• What event will mark the end.

When the grounds are vague, future discussion becomes simple: the employee claims the position was permanent and the company cannot prove otherwise.

Essential clauses in a contract for an indefinite term

An uncertain term contract can be short, but it cannot be loose.

In practical terms, it should include:

• identification of the parties;
• Workplace;
• Category and functions;
• Remuneration and components;
• Working hours and pattern;
• start date;
• express indication that it is for an uncertain term;
• tangible basis of the term;
• reference to the event that determines expiry;
• Communication rules for termination.

The clearer the writing, the less room there is for conflict.

Duration and limits: can it last forever?

No. And this is one of the most dangerous confusions.

Although the date is uncertain, the uncertain term is not unlimited. The law provides maximum limits for this type of contract. When the limit is exceeded, the contract may become an indefinite-term contract.

Furthermore, even before reaching the limit, if the company keeps the worker performing permanent duties, or if the temporary reason has already ended and the relationship continues, the risk of conversion increases.

The practical message is simple: the uncertain term must have a short lifespan in a legal sense, even if the date is not fixed.

Workers' rights on an indefinite-term contract

An uncertain fixed-term contract is an employment contract. The worker has employment rights like any other, including:

• Remuneration and receipts;
• holiday, holiday pay and Christmas bonus;
• support in parenting and illness;
• Working time and rest rules;
• Health and safety in the workplace;
• harassment and discrimination protection.

The fact that it is “fixed-term” does not reduce basic rights. What changes is the method of termination and, in certain cases, the compensation at the end.

If you have questions about termination by the employee, you can see Termination of contract by the employee: what are your rights and how to act.

How does a contract with an indefinite term end?

The uncertain-term contract expires by lapse when the reason that justified it ceases to exist.

Simple examples:

• The replaced worker returns.;
• the work ends;
• The project is completed.;
• The exceptional peak of activity ends.

All the more carefully: it is not enough for “the company to think” that it has ended. There must be real correspondence with the written grounds.

Furthermore, the company has communication duties. The end should not be a surprise sprung on the last day without proper form.

Notice period on expiry: what the employer has to comply with?

In practice, the expiry of a contract of indeterminate duration requires prior notice to the employee, with notice that may vary depending on the length of the employment relationship.

The purpose of notice is to provide minimum predictability for the worker, even in a contract without a set end date.

When notice is not given, there can be consequences, including payment of compensation corresponding to the outstanding period.

If a termination is being analysed and irregularities are suspected, it may be useful to frame the topic within the non-compliance and evidence plan in Breach of contract: what to do legally.

Compensation for expiry: does it always exist?

In many cases, there is a right to compensation when the forward contract expires.

The value depends on applicable legal rules and the time worked. The important point is this: compensation is not “a bonus”. It is a way of balancing the instability of a fixed-term contract.

When the company terminates the contract without respecting procedures, or when there is a dispute about conversion to an indefinite term, the issue of compensation may overlap with other indemnities.

Conversion to an indefinite contract: when the uncertain term ceases to apply

This is the most relevant topic for many people.

A contingent term contract can be considered an indefinite term contract when:

• there is no valid basis or the basis is insufficient;
• The reason given is not temporary;
• The contract exceeds legal limits.;
• does renewal or continuity of functions exist beyond the motive;
• there is an abuse of the figure to cover permanent needs.

In practice, the conversion could mean that to end the relationship, the company would have to follow dismissal rules with cause, or negotiate a settlement, rather than simply declaring “termination”.

This is one of the points where the analysis of documents and of the reality of daily work is decisive.

What to do if you suspect your indefinite term contract is illegal?

If you are a worker and you suspect that the contract has been used for a permanent need, the first rule is simple: do not act on impulse.

A prudent course of action involves:

• gather contract and addenda;
• save job descriptions, emails and evidence of permanent tasks;
• Map dates: start, role changes, continuation after reason end.;
• verify if there was formal communication of the grounds and the termination event;
• Seek legal advice before signing any exit documents.

If you are being pressured to sign, the risk is losing leverage. Signing closes doors.

What to do if you are an employer and want to use uncertain terms with confidence?

From the company's perspective, the aim should be to prevent, not to remedy.

Safe use involves:

• choose an uncertain term only when the reason is truly uncertain and temporary;
• write concrete and verifiable reasoning;
• aligning roles with the purpose and preventing the worker from being a permanent “stop-gap”;
• control deadlines and limits;
• Prepare the communication of expiry in advance;
• save proof of the event that justifies the end.

Document management is a part of risk. When a company cannot prove something, it loses leverage.

Uncertain term and unemployment benefit: what usually happens?

Many people associate the term "unemployment benefit" with automatic access to subsidies. In practice, access to benefits depends.

The key point is that expiry by term, when it occurs under legal terms, tends to be seen as termination at the employer's initiative, which, as a rule, is more compatible with involuntary unemployment than termination by the worker.

Nevertheless, each case depends on proof and context, so it is wise not to decide based solely on hearsay.

Common errors that create conflict

There are errors that repeat in contracts for an uncertain term.

• Generic basis with no real link to the functions.
• Use of the term uncertain for permanent functions.
• Lack of proof of the cessation event.
• Lack of prior notice of lapse.
• Continuation of employment after the supposed end of the reason.
• Confusing add-ons that try to “patch up” what started badly.

Avoiding these mistakes is cheaper than arguing afterwards.

Conclusion

The indefinite term contract is a legal tool for temporary needs without a defined end date. It is not a shortcut for keeping workers in permanent instability.

When used correctly, it.

If you have any doubts about your contract, the legality of an uncertain term, notice periods, compensation, or conversion to a permanent contract, speak to our lawyers in Braga and approach the subject with rigour.

If you are looking for a Solicitor To analyse documentation, guide your position and define the best next step, we are available to help.