In short

A conditional sentence pairs an if-clause (the condition) with a main clause (the result), and Portuguese sorts them into three types by how real the condition is: real (it may well happen), present-unreal (contrary to fact now, or a remote future), and past-unreal (it did not happen). Each type locks the two clauses into a fixed pair of tenses - and the single biggest surprise for English speakers is that a real future condition takes the future subjunctive after se (Lesson 36), where English just uses the present: Se tiveres tempo (“If you have time”). Get the pairings automatic and you can hypothesise, promise, regret and speculate with confidence. This lesson assembles tools you already have: the future subjunctive (#36), the imperfect subjunctive (#46), the conditional (#32) and the past-unreal pair (#48).

The rule

Type 1 - Real conditions (open or likely)

Use this when the condition is a genuine possibility - a general truth or a real future.

• General truth / habit: se + present indicative, main clause in the present. Se aqueces gelo, derrete. (If you heat ice, it melts.)
• Real future: se + futuro do conjuntivo, main clause in the present, future or imperative. Se chover amanhã, ficamos em casa. (If it rains tomorrow, we’ll stay home.) Se puderes, telefona-me. (If you can, call me.)

This is the make-or-break EP point. English keeps the present tense after “if” even for the future (“if you have time”, “if it rains”); Portuguese switches to the future subjunctive: tiveres, chover, puderes, fizeres. Never a future indicative and never a present subjunctive after se.

Type 2 - Present-unreal (hypothetical)

Use this for a situation contrary to present fact, or a remote/imagined future: se + pretérito imperfeito do conjuntivo, result in the condicional.

• Se tivesse dinheiro, compraria um carro. (If I had money, I would buy a car - but I don’t.)
• Se fosses mais cedo, apanhavas o comboio. (If you left earlier, you’d catch the train.)

In everyday European Portuguese the imperfeito do indicativo very commonly replaces the conditional in the result clause: comprava for compraria, apanhavas for apanharias. Both are correct; the conditional is the more formal or written choice, the imperfeito the more spoken one.

Type 3 - Past-unreal (it did not happen)

Use this to talk about a past that turned out otherwise - regret, reproach, speculation: se + pretérito mais-que-perfeito composto do conjuntivo (tivesse + participle), result in the condicional composto (teria + participle).

• Se tivesses estudado, terias passado no exame. (If you had studied, you would have passed the exam.)
• Se não tivesse chovido, tínhamos ido à praia. (If it hadn’t rained, we would have gone to the beach.)

Here too, the compound indicative pluperfect (tinha + participle) often stands in for the teria form in speech: tínhamos ido alongside teríamos ido.

Mixing the timeframes

The condition and the result do not have to share a tense. A very natural pattern is a past condition with a present result - se + MQP do conjuntivo -> condicional simples:

• Se tivesse estudado medicina, agora seria médico. (If I had studied medicine, I’d be a doctor now.)

Beyond se: other conditional connectors

Se is the workhorse, but caso, desde que (provided that), a não ser que / a menos que (unless) also introduce conditions - and, unlike se, they take the present subjunctive, not the future subjunctive:

• Caso precises de ajuda, diz. (Should you need help, say so.) - Caso precises, never Caso precisares.
• Levo o carro, a não ser que prefiras andar a pé. (I’ll take the car, unless you’d rather walk.)

Forms & patterns

The three types at a glance:

The two se-clause tenses for four key irregular verbs (these are the forms you actually build conditions on):

For type 3, take the ter imperfeito do conjuntivo above and add a participle: tivesse feito, tivesses estudado, tivéssemos ido.

Examples

Common mistakes

• Present indicative after se for the future: Se tens tempo amanhã -> Se tiveres tempo amanhã - a real future condition takes the futuro do conjuntivo, not the present.
• Future indicative after se: Se terei tempo -> Se tiver tempo - se never governs the future indicative; use the future subjunctive.
• Conditional inside the se-clause: Se compraria uma casa, se tivesse dinheiro -> Se tivesse dinheiro, compraria uma casa - the conditional belongs in the result; the se-clause takes the imperfeito do conjuntivo.
• Imperfeito do indicativo in a type-2 condition: Se tinha dinheiro, comprava (as a hypothesis) -> Se tivesse dinheiro, comprava - the condition needs the imperfeito do conjuntivo (tivesse), not the indicative (tinha).
• Present subjunctive after se: Se tenha tempo -> Se tiver (future) or Se tenho (general truth) - the present subjunctive never follows se.
• Simple past tenses for a past-unreal: Se estudavas, passavas (as a regret about what did not happen) -> Se tivesses estudado, terias passado - past-unreal needs the compound forms.

Tips

• Learn each type as a locked pair: real future = se + futuro do conjuntivo -> present/imperative; present-unreal = se + imperfeito do conjuntivo -> condicional; past-unreal = se + MQP do conjuntivo -> condicional composto.
• Drill the one habit English never prepares you for: after se about the future, use tiver, fores, puder, fizer, chover - the future subjunctive - where English uses a plain present.
• In real EP speech the imperfeito do indicativo freely replaces the conditional in a type-2 result: Se pudesse, ia is as natural as Se pudesse, iria; the same holds for tinha ido vs teria ido in type 3.
• Mix freely when the logic demands it: a past condition can carry a present result - Se tivesse aceitado o emprego, agora estaria em Berlim.
• Keep the connectors straight: se takes the future subjunctive, but caso, desde que, a não ser que take the present subjunctive - Caso chova, never Caso chover.
• In Brazil the three structures are identical; the audible difference is again the result clause, where the imperfeito do indicativo (Se pudesse, ia) dominates spoken usage even more than in Portugal (Lesson 10).