The futuro do conjuntivo — the future subjunctive — is one of the most distinctive features of Portuguese grammar, and one of the most useful tenses you will ever learn. It handles a huge range of everyday sentences: quando tiveres tempo (when you have time), se puderes (if you can), enquanto estiver aqui (while I'm here), assim que chegares (as soon as you arrive). It is alive, productive, and encountered multiple times a day in ordinary conversation.
The crucial thing to know upfront: Portuguese is almost alone among modern Romance languages in keeping this tense as a living feature. Spanish has essentially lost it — you meet it only in frozen legal phrases (sea como fuere) and proverbs. French never had it. Italian has a small literary remnant. Portuguese — both European and Brazilian — uses the full future subjunctive every day. If you come to Portuguese from another Romance language, do not underestimate this tense. You will need it.
What the future subjunctive actually does
The future subjunctive marks a verb that refers to an uncertain future event inside certain kinds of subordinate clause. The situation is not yet real, not yet settled; it might happen, and when (or if) it does, the main clause event follows.
Quando eu chegar, ligo-te.
When I arrive, I'll call you.
Se tiver tempo, passo por aí.
If I have time, I'll drop by.
Assim que souberes a resposta, diz-me.
As soon as you know the answer, tell me.
Enquanto estiver aqui, vou aproveitar ao máximo.
While I'm here, I'm going to make the most of it.
English uses the present tense for these contexts (when I arrive, if I have time, as soon as you know). Portuguese uses the future subjunctive. This is one of the clearest and most important differences between the two grammatical systems, and one of the highest-value rules to internalise.
Why the future subjunctive exists
The future subjunctive exists because Portuguese takes tense and mood very seriously. A future event is not yet real — so it is already a candidate for subjunctive mood. But the future subjunctive is reserved specifically for contexts where the timing of the future event matters: the main clause is waiting on the subordinate event, anchored to it, or conditional on it.
Think of it this way:
- Quero que venhas (I want you to come) — the coming is a wish, timing unspecified → present subjunctive.
- Quando vieres, avisa-me (When you come, let me know) — the coming is expected or possible, and the main clause action is timed to it → future subjunctive.
The difference is not about the certainty of the event. It is about whether the subordinate clause is framing a wish / evaluation (present subjunctive) or a temporal / conditional anchor (future subjunctive). Once you feel this distinction, the tense choice becomes automatic.
Why Spanish learners get tripped up here
A tragedy of comparative grammar: the future subjunctive existed in Old Spanish and Old Portuguese alike, but Spanish abandoned it in regular speech centuries ago. Modern Spanish uses the present subjunctive after cuando, si, en cuanto, mientras: cuando llegues, avísame. Portuguese kept both the form and the distinction, and now uses the future subjunctive in exactly these contexts: quando chegares, avisa-me.
This means Spanish speakers learning Portuguese routinely reach for the present subjunctive — quando chegues instead of quando chegares, se tenhas instead of se tiveres — and the result sounds immediately wrong to Portuguese ears. The single most impactful correction a Spanish speaker can make is learning to put the future subjunctive after these triggers.
❌ Quando chegues, avisa-me. (Spanish influence)
Wrong in Portuguese.
✅ Quando chegares, avisa-me.
Let me know when you arrive.
Italian and French speakers have a milder version of the same problem. Both languages use the present indicative after quando / quand + future (quando arriverai, mi chiami; quand tu arriveras, appelle-moi). Portuguese uses the future subjunctive. Train yourself to reach for it.
The triggers: where the future subjunctive lives
The future subjunctive has a tight, learnable list of triggers. You see it in three main families of clauses: temporal, conditional, and relative with indefinite antecedents. Plus a handful of manner / comparison conjunctions that join the club.
1. Temporal conjunctions
When the main clause event is timed to a future subordinate event, you get the future subjunctive.
| Conjunction | Meaning | Example |
|---|---|---|
| quando | when | Quando chegares, liga-me. |
| assim que | as soon as | Assim que acabar, vou ter contigo. |
| logo que | as soon as | Logo que souberes, avisa-me. |
| enquanto | while, as long as | Enquanto estiveres cá, aproveita. |
| sempre que | whenever, every time | Sempre que passares por Lisboa, diz. |
| depois que | after (something happens) | Depois que comeres, vemos o filme. |
| mal | the moment (that), as soon as | Mal chegares, diz-me. |
Quando acabares o curso, o que vais fazer?
When you finish the course, what are you going to do?
Assim que o comboio chegar, avisem-me.
As soon as the train arrives, let me know.
Sempre que vieres a Lisboa, ficas cá em casa.
Whenever you come to Lisbon, you stay at our place.
2. Conditional se — the big one
After se meaning "if," when the condition is a real possibility in the future, Portuguese uses the future subjunctive. This is the type-1 conditional structure.
Se tiver tempo amanhã, vou ao cinema.
If I have time tomorrow, I'll go to the cinema.
Se chover, ficamos em casa.
If it rains, we'll stay home.
Se puderes, liga-me assim que chegares.
If you can, call me as soon as you get there.
Se não quiseres vir, compreendo perfeitamente.
If you don't want to come, I completely understand.
Note the contrast with hypothetical se (type-2 conditionals), which takes the imperfect subjunctive because the condition is unreal, not just unsettled:
Se tivesse tempo amanhã, ia ao cinema.
If I had time tomorrow, I'd go to the cinema. (hypothetical — imperfect subjunctive)
The distinction hinges on the speaker's attitude: se tiver frames the possibility as open and realistic; se tivesse frames it as unlikely, imagined, or counterfactual. See conditional in hypothetical sentences for the full comparison.
3. Relative clauses with indefinite antecedents (using quem, o que, onde)
When a relative pronoun refers to an entity whose identity or existence is uncertain, and the reference points into the future, Portuguese uses the future subjunctive.
Quem chegar primeiro, guarda mesa.
Whoever arrives first, save a table.
O que tu decidires, eu apoio.
Whatever you decide, I'll support.
Onde tu fores, eu vou também.
Wherever you go, I'll go too.
Faremos o que for preciso.
We'll do whatever is needed.
The last example uses for (future subjunctive of ser) — a small but very common word that learners often stumble over. We will come back to it.
4. Manner / comparison conjunctions
A smaller group of conjunctions of manner and comparison take the future subjunctive when pointing to an as-yet-undetermined future:
| Conjunction | Meaning |
|---|---|
| como | as, however (manner) |
| conforme | as, according to |
| segundo | according to, as |
Faz como quiseres.
Do as you like.
Decidiremos conforme as circunstâncias o exigirem.
We'll decide as circumstances require.
Segundo aquilo que descobrirmos, mudamos o plano.
Based on what we find out, we'll change the plan.
A teaser conjugation: chegar
To show what the forms look like before the dedicated regular forms page, here is chegar (to arrive) in the future subjunctive:
| Subject | Future Subjunctive |
|---|---|
| eu | chegar |
| tu | chegares |
| ele / ela / você | chegar |
| nós | chegarmos |
| eles / elas / vocês | chegarem |
Quando eu chegar, ligo-te.
When I arrive, I'll call you.
Quando tu chegares, avisa-me.
When you arrive, let me know.
Quando chegarmos, jantamos.
When we arrive, we'll have dinner.
Notice: for a regular verb like chegar, the future subjunctive 1sg and 3sg forms (chegar) are identical to the infinitive. This is not a coincidence — the future subjunctive is built from the same stem as the personal infinitive. We explore this in detail on the regular forms page.
The two most important irregular stems
Two verbs you will meet constantly in the future subjunctive are ser/ir and ter. Their future subjunctive stems are irregular and must be learned.
| Verb | eu | tu | ele | nós | eles |
|---|---|---|---|---|---|
| ser / ir | for | fores | for | formos | forem |
| ter | tiver | tiveres | tiver | tivermos | tiverem |
Se for preciso, eu vou.
If it's necessary, I'll go.
Quando tiveres tempo, lê isto.
When you have time, read this.
Quem for ao supermercado, que traga pão.
Whoever goes to the supermarket, bring bread.
The form for is especially striking because it serves both ser ("be") and ir ("go") — inherited from the identical preterite fui / foi / foram shared by those two verbs. Context decides.
The full irregular paradigms live on the irregular forms page.
How the future subjunctive pairs with main clause tenses
The main clause that accompanies a future subjunctive clause is usually in one of four shapes:
- Present indicative (for near-certain future): Se tiveres tempo, passa cá em casa.
- Ir + infinitive (for explicit future): Quando chegares, vamos jantar.
- Simple future indicative (for formal or written register): Assim que o relatório estiver pronto, enviá-lo-ei.
- Imperative (for requests): Quando souberes, diz-me.
Se puderes, passa cá em casa depois do trabalho.
If you can, come by after work.
Quando chegares, vamos jantar fora.
When you arrive, we're going out for dinner.
Assim que o contrato estiver assinado, enviaremos a confirmação.
As soon as the contract is signed, we will send the confirmation. (formal)
Mal souberes, diz-me.
The moment you know, tell me.
Everyday examples — the feel of the tense
Here is the future subjunctive in the kinds of sentences you will actually produce and hear every day.
Quando eu souber, digo-te.
When I know, I'll tell you.
Se chover amanhã, adiamos o piquenique.
If it rains tomorrow, we'll postpone the picnic.
Assim que o bebé acordar, vamos dar um passeio.
As soon as the baby wakes up, we'll go for a walk.
Enquanto eu estiver a cozinhar, podes pôr a mesa?
While I'm cooking, can you set the table?
Sempre que fores a Sintra, come uma queijada.
Whenever you go to Sintra, have a queijada.
Onde quer que estejas, pensa em mim.
Wherever you are, think of me. (*onde quer que* is a fixed expression that takes the present subjunctive — *estejas* — not the future subjunctive. Bare *onde* takes the future subjunctive: *onde estiveres*.)
Quem tiver interesse, que se inscreva até sexta-feira.
Whoever is interested, sign up by Friday.
Se não for hoje, será amanhã.
If not today, it'll be tomorrow.
Register and frequency
The future subjunctive is register-neutral: you use it identically in a text message to a friend and in a formal legal document. Quando puderes is what you write to your best friend; quando puderem is what a bank writes to customers. There is no informal alternative that avoids it — you cannot duck the future subjunctive by switching to a casual form. Every native European Portuguese speaker, regardless of age, education, or region, uses this tense fluently every day.
This is a key reason to prioritise it in your learning. You cannot speak good Portuguese without the future subjunctive. There is no workaround.
The dedicated pages
This overview sketches the territory. The full details live on two dedicated pages:
- Regular forms — how to build the future subjunctive from any regular verb, the homograph relationship with the personal infinitive, and the full paradigms for all three conjugations.
- Irregular forms — the handful of verbs (ser, ir, ter, estar, vir, ver, saber, poder, fazer, dizer, trazer, querer, pôr, and a few more) whose future subjunctive stems do not follow the regular recipe.
Comparison with English
English uses the present indicative in almost all of these contexts:
| English | Portuguese |
|---|---|
| When I arrive, I'll call you. | Quando chegar, ligo-te. |
| If I have time, I'll go. | Se tiver tempo, vou. |
| As soon as you know, tell me. | Assim que souberes, diz-me. |
| While I'm there, I'll visit. | Enquanto estiver lá, vou visitar. |
| Whenever you come, you're welcome. | Sempre que vieres, és bem-vindo. |
| Whoever wants, can come. | Quem quiser, pode vir. |
The English pattern is flatter: present indicative in the when/if clause, future in the main clause. Portuguese layers the mood difference explicitly: future subjunctive in the when/if clause, because the event is not yet settled.
A pitfall for English speakers
Because English lets you use the present so freely in these contexts, there is a strong pull toward saying quando chego (present indicative) or even quando chegarei (future indicative) where Portuguese wants quando chegar (future subjunctive). Neither of the English-influenced choices works in standard Portuguese. Train your ear: after quando referring to a future event, you reach for the future subjunctive. Always.
Common Mistakes
❌ Quando eu chego, ligo-te.
Incorrect — present indicative where future subjunctive is required.
✅ Quando eu chegar, ligo-te.
When I arrive, I'll call you.
This is the most common single error. English-influenced learners default to the present indicative after quando. Portuguese requires the future subjunctive.
❌ Se eu terei tempo, vou ao cinema.
Incorrect — future indicative after *se*.
✅ Se eu tiver tempo, vou ao cinema.
If I have time, I'll go to the cinema.
After se meaning "if" in a realistic future clause, never the future indicative. Always the future subjunctive: tiver, not terei.
❌ Assim que ele chegue, começamos.
Spanish-influenced — present subjunctive instead of future subjunctive.
✅ Assim que ele chegar, começamos.
As soon as he arrives, we start.
Spanish says en cuanto llegue; Portuguese says assim que chegar. The future subjunctive is the Portuguese hallmark.
❌ Quem quer vir, levanta a mão.
Ambiguous — this reads as a present statement (whoever wants to come now), not a future invitation.
✅ Quem quiser vir, levante a mão.
Whoever wants to come, raise your hand. (future / open invitation)
After indefinite quem referring to an unspecified / future respondent, use the future subjunctive. Notice also the imperative levante — formal register matches formal register.
❌ Enquanto ele está lá, vai aprender muito.
Mismatch — the main clause is future, but the subordinate is present indicative.
✅ Enquanto ele estiver lá, vai aprender muito.
While he's there, he'll learn a lot.
If the whole situation is future, enquanto demands the future subjunctive estiver.
❌ Sempre que vens a Lisboa, jantamos juntos.
Generic-habitual only — reads as a routine, not an open invitation. Correct if that is the meaning.
✅ Sempre que vieres a Lisboa, jantamos juntos.
Whenever you come to Lisbon, we'll have dinner together. (open future)
Sempre que with the future subjunctive signals "each time you come in future." Sempre que with the present indicative signals habitual ongoing practice. Both are valid Portuguese; pick the one that matches your meaning.
Key takeaways
- The futuro do conjuntivo is a living, everyday tense in European Portuguese — used after temporal, conditional, and relative-clause triggers that point at an uncertain future event.
- Common triggers: quando, se, assim que, logo que, enquanto, sempre que, depois que, mal, como, conforme, quem, o que, onde.
- Spanish lost this tense; Portuguese kept it. Spanish-influenced quando chegue is wrong in Portuguese; it must be quando chegar.
- Regular verbs build the future subjunctive from the 3pl preterite minus -am — and the singular form coincides with the infinitive, which is a useful memory hook.
- The main irregular stems to memorise are for (ser/ir), tiver (ter), estiver (estar), puder (poder), quiser (querer).
- There is no informal alternative. You will use this tense every day, in every register. Make friends with it.
Next: learn how to actually build it, starting with regular forms and then irregular forms.
Related Topics
- Subjunctive Mood OverviewB1 — What the conjuntivo is in European Portuguese, why it exists, and when the language requires it — a tour of irrealis across the present, imperfect, and future subjunctive
- Regular Future Subjunctive FormsB1 — How to build the future subjunctive from any regular verb — take the 3pl preterite, drop -am, add the endings. Full paradigms for -ar, -er, and -ir verbs, plus the remarkable homograph relationship with the personal infinitive.
- Irregular Future Subjunctive FormsB1 — The handful of Portuguese verbs whose future subjunctive is built from an irregular preterite stem — ser/ir, ter, estar, poder, querer, saber, fazer, dizer, trazer, vir, ver, pôr, dar, haver — with full paradigms and use in everyday sentences.
- Present Subjunctive OverviewB1 — How the presente do conjuntivo is formed, why it exists, and the five big families of situations that trigger it.
- Conditional in Hypothetical SentencesB1 — How the conditional pairs with the imperfect subjunctive to describe hypothetical, counterfactual, and unreal situations.
- If-Clauses with the Imperfect SubjunctiveB1 — Se + imperfeito do conjuntivo + conditional (or imperfect indicative): the core Portuguese pattern for hypothetical and counterfactual conditions — plus the three-way contrast between open, hypothetical, and past-impossible conditions.