Si clauses (conditional sentences)

Summary

French conditional sentences pair a si-clause with a result clause in three fixed patterns: si + present → present/future/imperative; si + imparfait → conditionnel présent; si + plus-que-parfait → conditionnel passé. The conditional and the future never appear directly after si.

Explanation

A French conditional sentence has two parts: the subordinate clause introduced by si ('if'), which states the condition, and the main clause, which states the result. The two clauses can come in either order: « Si tu veux, on y va » means the same as « On y va si tu veux. » The single most important rule is that the conditional and the future tenses never appear immediately after si. Where English allows « if I would have », French does not: the conditional lives only in the result clause.

Pattern 1 — the real, open condition: si + présent in the if-clause, and the présent, the futur simple, or the impératif in the result clause. This expresses something likely or habitual: « Si tu veux, on y va » (present), « Si j'ai le temps, je viendrai » (future), « Si tu as faim, mange quelque chose » (imperative). The condition is presented as a genuine possibility.

Pattern 2 — the unreal present (or unlikely) condition: si + imparfait in the if-clause, and the conditionnel présent in the result clause. This describes a situation contrary to present fact or felt as improbable: « Si j'avais le temps, je viendrais » ('If I had time, I would come' — but I don't). The imparfait here is not a past tense; it is the form the hypothesis requires.

Pattern 3 — the unreal past condition: si + plus-que-parfait in the if-clause, and the conditionnel passé in the result clause. This expresses a regret or a hypothesis about something that did not happen: « Si j'avais su, je serais venu » ('If I had known, I would have come'). The plus-que-parfait sets the unreal past condition; the conditionnel passé gives its unrealised consequence.

Two spelling and form points matter. First, si elides to s' only before il and ils: « s'il pleut », « s'ils viennent », but never before elle/elles or on (« si elle veut », « si on part »). Second, do not confuse the conditional si with the si that means 'whether' in indirect questions (« Je me demande s'il viendra »); that si can be followed by a future or a conditional because it is not introducing a hypothesis at all.

A useful memory aid is to lock the three pairs together: présent ↔ présent/futur/impératif, imparfait ↔ conditionnel présent, plus-que-parfait ↔ conditionnel passé. If you can name the tense in the si-clause, the result clause is fixed; if you find yourself wanting a conditional after si, you have almost certainly chosen the wrong half of a pair.

Examples

Si tu veux, on y va. — If you want, we'll go. (Pattern 1: si + présent → présent (real, open condition).)

Si j'ai le temps, je viendrai. — If I have time, I'll come. (Pattern 1: si + présent → futur simple.)

Si tu as faim, mange quelque chose. — If you're hungry, eat something. (Pattern 1: si + présent → impératif.)

Si j'avais le temps, je viendrais. — If I had time, I would come. (Pattern 2: si + imparfait → conditionnel présent (unreal present).)

Si j'avais su, je serais venu. — If I had known, I would have come. (Pattern 3: si + plus-que-parfait → conditionnel passé (unreal past).)

S'il pleut demain, nous resterons à la maison. — If it rains tomorrow, we'll stay home. (si elides to s' only before il/ils.)

Common mistakes

Prerequisites

• Present conditional

Related rules

• Present conditional
• Conditionnel passé
• Imparfait
• Plus-que-parfait