If there is one grammar feature that ambushes English speakers learning Brazilian Portuguese, it is this one. When you talk about a future event introduced by quando ("when"), se ("if"), assim que ("as soon as") and a handful of related conjunctions, Portuguese requires the future subjunctive — a tense English does not have and does not expect. Where English happily says "When you arrive, call me" (present tense), Portuguese says Quando você *chegar, me liga* (future subjunctive). Mastering this single pattern transforms how natural your Portuguese sounds.
The core rule
After certain conjunctions of time and condition, if the event is in the future (or generally hypothetical), use the future subjunctive. The trigger conjunctions are:
- quando — when
- se — if
- enquanto — while / as long as
- assim que — as soon as
- logo que — as soon as
- depois que — after
- sempre que — whenever
- conforme — as / depending on how
- como — as / however (in the sense of "in whatever way")
Quando você chegar, me avise.
When you arrive, let me know.
Se ele vier, fica tudo bem.
If he comes, everything will be fine.
Enquanto você estiver fora, eu cuido da casa.
While you're away, I'll look after the house.
In every one of these, the event has not happened yet — arriving, coming, being away are all future or unrealized. That is the condition that switches on the future subjunctive.
Why English speakers get this wrong
English uses the present indicative for future events after these conjunctions — a quirk grammarians call the "present-for-future" rule. We say "When you get home," "As soon as he finishes," "If it rains," all with present-tense verbs even though we mean the future. English speakers then transfer that habit directly into Portuguese and produce the wrong tense:
| English (present indicative) | Portuguese (future subjunctive) |
|---|---|
| When you arrive... | Quando você chegar... |
| As soon as I know... | Assim que eu souber... |
| If he comes... | Se ele vier... |
| While you are away... | Enquanto você estiver fora... |
The deep logic is that Portuguese has a dedicated form for "an event located in the future and not yet certain," and it insists on using it. English collapsed that meaning into the present tense centuries ago, so we no longer feel the distinction. Portuguese keeps it sharp.
Assim que eu souber, te conto.
As soon as I know, I'll tell you.
Depois que vocês terminarem, podem sair.
After you all finish, you can leave.
Sempre que você precisar, é só me ligar.
Whenever you need, just call me.
Present vs. future event: the same conjunction, two tenses
The same conjunction can take the present indicative when it describes a habitual or current fact, and the future subjunctive when it points to a specific future event. The contrast is real and meaningful.
| Habitual / current (indicative) | Specific future (future subjunctive) |
|---|---|
| Quando chove, eu fico em casa. (When it rains, I stay home — a general habit.) | Quando chover amanhã, eu fico em casa. (When it rains tomorrow, I'll stay home — one future event.) |
| Sempre que ele vem, traz um presente. (Whenever he comes, he brings a gift — habit.) | Quando ele vier, vamos conversar. (When he comes, we'll talk — future.) |
Quando o sinal abrir, a gente atravessa.
When the light turns green, we'll cross.
Enquanto eu estiver de férias, não vou responder e-mails.
While I'm on vacation, I won't answer emails.
se: future condition vs. hypothetical
Se deserves a careful note because it splits two ways. For a real, open future condition ("if X happens, then Y"), use the future subjunctive: Se chover, eu levo guarda-chuva ("If it rains, I'll take an umbrella" — it might genuinely rain). For a contrary-to-fact or unlikely condition ("if I were rich"), use the imperfect subjunctive instead: Se eu fosse rico.... Do not confuse the two.
Se ele chegar a tempo, a gente vai junto.
If he arrives in time, we'll go together. (open future — future subjunctive)
Se eu tivesse tempo, eu iria com vocês.
If I had time, I'd go with you. (hypothetical — imperfect subjunctive)
Common Mistakes
❌ Quando você chega, me avise.
Incorrect — present indicative 'chega' for a future event; needs the future subjunctive.
✅ Quando você chegar, me avise.
When you arrive, let me know.
The flagship error: copying the English present "when you arrive" straight into chega. The future event requires chegar.
❌ Se ele vem amanhã, a gente sai.
Incorrect — for a real future condition use the future subjunctive 'vier'.
✅ Se ele vier amanhã, a gente sai.
If he comes tomorrow, we'll go out.
❌ Assim que eu sei, te conto.
Incorrect — 'sei' is present indicative; the future event needs 'souber'.
✅ Assim que eu souber, te conto.
As soon as I know, I'll tell you.
❌ Quando você chegará, me avise.
Incorrect — the future indicative 'chegará' doesn't belong after 'quando'.
✅ Quando você chegar, me avise.
When you arrive, let me know.
Overcorrecting from present to future indicative is just as wrong. Time conjunctions take the future subjunctive, not the future indicative.
❌ Enquanto você está fora, eu cuido da casa. (referindo-se a uma viagem futura)
Incorrect for a future trip — 'está' (present) should be 'estiver' (future subjunctive).
✅ Enquanto você estiver fora, eu cuido da casa.
While you're away, I'll look after the house.
Key Takeaways
- After quando, se, enquanto, assim que, logo que, depois que, sempre que, conforme, como — when the event is in the future — use the future subjunctive.
- English uses the present indicative here ("when you arrive"); Portuguese uses the future subjunctive (quando você chegar). This is the single biggest surprise for English speakers.
- The same conjunction takes the present indicative for habits/general truths and the future subjunctive for specific future events.
- For se: open future condition → future subjunctive (se chover); contrary-to-fact → imperfect subjunctive (se eu fosse rico).
- Do not use the future indicative (chegará) after these conjunctions.
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Start learning Portuguese→Related Topics
- Futuro do Subjuntivo: FormationA2 — How to build the future subjunctive in Brazilian Portuguese — derived from the third-person plural preterite, and why it looks deceptively like the infinitive.
- Conjunctions of Time + SubjunctiveB1 — Temporal conjunctions like quando, assim que and antes que that govern the future subjunctive for future events — and the outlier antes que, which always takes the subjunctive.
- Indicative vs Subjunctive: Decision GuideB1 — A practical guide to choosing the indicative or subjunctive in Portuguese using the assertion test, trigger lists, and the negation flip with verbs like achar.
- Future Subjunctive vs Future IndicativeB1 — Why 'quando você chegar' (future subjunctive) pairs with a main-clause future like 'eu vou te ligar' — how the two halves of a future sentence each pick their own form.
- Present Indicative for Future EventsA2 — How Brazilian Portuguese uses the simple present for scheduled and near-future events — like English 'the train leaves at five' — and how this choice differs from vou + infinitivo and the simple future.