The Portuguese Future Subjunctive: Quando, Se, and Assim Que
Use the future subjunctive for a possible future action after words like quando and se: quando eu chegar, se você quiser.
Real Life Portuguese · 8 min read · Updated October 14, 2026
The short answer
Brazilian Portuguese often uses the future subjunctive after quando (when), se (if), and assim que (as soon as) when the clause refers to a future event that has not happened yet. The tense describes the timing and uncertainty of the event; English usually uses a present form in the same kind of clause.
Use the future subjunctive for a future possibility
The form is often easy to spot in irregular verbs: quando eu for (when I go), se você tiver (if you have), and assim que eles souberem (as soon as they know). For regular verbs, the future-subjunctive form commonly matches the infinitive for eu, você, ele, ela, and eles; the first-person plural often has its own form, such as quando nós falarmos.
Quando eu chegar em casa, vou te ligar.
When I get home, I’ll call you.
Se você quiser, a gente pode conversar depois.
If you want, we can talk later.
Assim que eles souberem o horário, vão avisar.
As soon as they know the time, they’ll let us know.
Build common forms from the past-tense stem
For many verbs, you can find the future subjunctive by starting with the third-person plural of the preterite, removing -am, and adding the matching ending. Falaram becomes falar, comeram becomes comer, and partiram becomes partir. The result looks like an infinitive for many persons, but it is a finite verb form and changes for nós: falarmos, comermos, partirmos.
Irregular verbs need their own forms, so learn frequent examples in short phrases. For ter, use tiver, tiveres, tiver, tivermos, tiverem; for fazer, use fizer, fizeres, fizer, fizermos, fizerem. In everyday Brazilian speech, você takes the same form as ele or ela: se você fizer.
Quando nós terminarmos, podemos sair.
When we finish, we can leave.
Se ela fizer a reserva, eu confirmo o endereço.
If she makes the reservation, I’ll confirm the address.
Quando vocês puderem, me mandem uma mensagem.
When you all can, send me a message.
Compare a real future condition with a regular habit
A future possibility often uses the subjunctive: Se eu tiver tempo amanhã, vou cozinhar. A repeated or generally true situation can use the present indicative: Se eu tenho tempo, eu cozinho em casa. The surrounding meaning—not the word se by itself—helps you choose.
Do not put the future subjunctive in the result clause simply because the first clause refers to the future. The result may use ir + infinitive, the present, or an imperative, depending on what you mean. Practice the whole sentence as a unit and listen for the verb forms after the time or condition word.
Se chover amanhã, vamos ficar em casa.
If it rains tomorrow, we’ll stay home.
Quando você chegar, me avisa.
When you arrive, let me know.
Se tenho uma dúvida, eu pergunto ao professor.
If I have a question, I ask the teacher.
Put it into practice
Choose a future plan and complete one frame aloud: “Quando eu…,” or “Se eu…”. Use the future subjunctive for the possible future event, then add the result you expect.
Quick practice
Which Portuguese example matches “When we finish, we can leave”?
Choose an answer to check yourself.
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