A conditional sentence in French has two halves: the si-clause, which introduces the condition, and the main clause (also called the apodosis), which states the consequence. The pairing of tenses across these two halves is fixed — it is not a stylistic choice. There are exactly three patterns, each expressing a different degree of likelihood, and learning them as a single triad is the fastest way to internalize French conditionals.
The three patterns differ in how real the condition is. Type 1 talks about something that may genuinely happen. Type 2 talks about something that is not the case right now (or is unlikely to happen). Type 3 talks about something that did not happen — it is irrevocably contrary to the past. Once you grasp this gradient, the tense choices feel almost mechanical.
The iron rule: si never takes the conditionnel
Before any of the three types, lock in this single non-negotiable principle: the verb in the si-clause is never in the conditionnel mood. Never. Not in any pattern. Not in any register. Not in any region.
A French teaching mnemonic captures this perfectly: "les si n'aiment pas les -rais" — "the si doesn't like the -rais endings." The conditionnel endings (-rais, -rais, -rait, -rions, -riez, -raient) are forbidden after si.
❌ Si je serais riche, j'achèterais une maison.
Incorrect — conditionnel after 'si' is one of the most stigmatized errors in French.
✅ Si j'étais riche, j'achèterais une maison.
If I were rich, I would buy a house.
Even native speakers of certain regional varieties sometimes produce si je serais; in standard French and in writing, it is treated as an unambiguous error. The si-clause uses only: présent, imparfait, or plus-que-parfait — depending on the type.
Type 1 — Real / likely conditional
Pattern: si + présent, main clause in futur simple (or présent, or impératif).
This is the conditional you use when the event is genuinely possible — when there is a real chance the condition will be met. English uses the same logic (If you come, I'll be happy).
Si tu viens demain, je serai content.
If you come tomorrow, I'll be happy.
S'il fait beau ce week-end, on ira pique-niquer au bord de la Loire.
If the weather is nice this weekend, we'll go picnicking by the Loire.
Si tu finis tes devoirs avant huit heures, tu pourras regarder un film.
If you finish your homework before eight, you'll be able to watch a film.
The si-clause here uses the présent, never the futur, even though the event is in the future. This matches English: we say if you come, not if you will come. (See verbs/future/si-with-present-not-future for the contrast with quand-clauses, which do take the futur.)
The main clause can also stay in the present tense if you are stating a general truth or a routine consequence:
Si tu chauffes l'eau à cent degrés, elle bout.
If you heat water to one hundred degrees, it boils.
Si tu as faim, il y a du pain dans le placard.
If you're hungry, there's bread in the cupboard.
Or the main clause can be an imperative — a command conditional on something:
Si tu vois Paul, dis-lui de m'appeler.
If you see Paul, tell him to call me.
S'il pleut, prends mon parapluie.
If it rains, take my umbrella.
Type 2 — Hypothetical present (unreal in the present, unlikely in the future)
Pattern: si + imparfait, main clause in conditionnel présent.
You use Type 2 when the condition is not currently true or is unlikely to become true. The imparfait here is not a past tense — it is what grammarians call the unreal imparfait, signalling that you are entering a hypothetical world.
Si j'avais le temps, je viendrais avec toi au cinéma.
If I had time, I'd come with you to the cinema.
Si j'étais à ta place, j'accepterais cette offre sans hésiter.
If I were in your shoes, I'd accept that offer without hesitating.
Si on vivait à la campagne, on aurait un jardin et des poules.
If we lived in the countryside, we'd have a garden and chickens.
Si tu étais plus gentil avec ta sœur, elle te prêterait ses affaires.
If you were nicer to your sister, she'd lend you her things.
The implicit message: I don't have the time, I'm not in your shoes, we don't live in the countryside, you're not being nice. Type 2 is the workhorse of advice, fantasy, and gentle hypothetical thinking. It is also extremely common in dreams, plans, and proposals.
A subtlety: French uses the imparfait here with the same form regardless of person or number. There is no equivalent of the English subjunctive were. Si j'étais riche, si tu étais riche, s'il était riche — all use the same indicative-looking imparfait. The hypothetical meaning comes from the pairing with the conditionnel in the main clause, not from a special verb form.
Type 3 — Counterfactual past (didn't happen)
Pattern: si + plus-que-parfait, main clause in conditionnel passé.
Type 3 talks about something that did not happen. It is the language of regret, of alternative histories, of "what would have been." Both halves of the sentence are unreal: the condition was not met, and as a result the consequence did not occur.
Si tu étais venu hier, tu aurais rencontré ma cousine.
If you had come yesterday, you would have met my cousin.
Si j'avais su qu'il y aurait autant de monde, je serais resté chez moi.
If I'd known there would be so many people, I'd have stayed home.
Si nous étions partis plus tôt, nous aurions évité les embouteillages.
If we'd left earlier, we would have avoided the traffic jams.
Si tu m'avais écouté, on n'en serait pas là.
If you had listened to me, we wouldn't be in this mess.
The plus-que-parfait (j'avais su, tu étais venu, nous étions partis) and the conditionnel passé (je serais resté, tu aurais rencontré, on n'en serait pas là) form a tight pair. Both halves anchor the sentence firmly in a past that did not happen.
Type 3 maps almost exactly to English "if + had + past participle, would have + past participle." The structures are parallel, and learners with a solid English grammar background pick up Type 3 quickly once they accept the rule that si takes the plus-que-parfait, never the conditionnel passé.
The big picture: a single comparison table
| Type | Si-clause | Main clause | Meaning |
|---|---|---|---|
| 1 — Real | présent | futur (or présent / impératif) | condition is plausible |
| 2 — Hypothetical | imparfait | conditionnel présent | condition is contrary to current reality, or unlikely |
| 3 — Counterfactual past | plus-que-parfait | conditionnel passé | condition was not met; the consequence did not happen |
A useful way to internalize the system is to take a single thought and run it through all three:
Si tu travailles, tu réussiras.
If you work hard, you'll succeed. (You might still do it — there's time.)
Si tu travaillais, tu réussirais.
If you worked hard, you'd succeed. (But you're not working hard.)
Si tu avais travaillé, tu aurais réussi.
If you had worked hard, you would have succeeded. (You didn't, and you didn't.)
Each step shifts the whole sentence one degree further into unreality.
Mixed conditionals
In real speech, people sometimes mix tenses across types when the timing of the condition and the timing of the consequence don't match up.
Si j'avais étudié la médecine, je serais médecin aujourd'hui.
If I had studied medicine, I'd be a doctor today.
The condition is in the past (si j'avais étudié — Type 3 form), but the consequence is in the present (je serais — Type 2 form). This makes sense: the action of studying happened (or didn't) in the past, but its effect would be ongoing today. Mixed conditionals are perfectly grammatical — they reflect the actual time relations of what you're describing.
Si j'étais plus organisé, j'aurais déjà fini ce projet.
If I were more organized, I would have already finished this project.
Here the condition is a permanent personality trait (si j'étais — Type 2), and the consequence is a missed past action (j'aurais fini — Type 3 form). Again, idiomatic and natural.
When the two clauses are reversed
The order main clause + si-clause is just as common as si-clause + main clause. The tense pattern stays the same; only the comma typically disappears.
Je serais content si tu venais demain.
I'd be happy if you came tomorrow.
On aurait évité l'accident si on avait roulé moins vite.
We would have avoided the accident if we had driven more slowly.
You will see both orders in writing and speech. Reversed-order conditionals are slightly more common in informal speech, where the speaker tends to lead with the consequence ("I'd love to") and then add the condition ("if I had time").
Si as "whether" — a different si entirely
Be careful: French si has another use that is not conditional at all. It introduces indirect yes/no questions, where it means whether in English. This si has different rules — in particular, it can take the futur or the conditionnel.
Je me demande si tu viendras à la soirée.
I'm wondering whether you'll come to the party.
Il a demandé si tu serais d'accord.
He asked whether you'd agree.
This si is an indirect question word, not a conditional connector. The fact that the same little word does both jobs is a coincidence of French syntax. The two si*s are easily distinguished by context: one introduces a hypothesis (*if you came), the other introduces an embedded question (whether you came).
Common Mistakes
The errors below are the highest-frequency errors English-speaking learners make with French conditionals. Each one corresponds to a specific transfer pattern from English.
❌ Si je serais riche, j'achèterais une maison.
Incorrect — never use conditionnel after 'si' in a conditional clause.
✅ Si j'étais riche, j'achèterais une maison.
If I were rich, I would buy a house.
This is the cardinal sin of French conditionals. English speakers sometimes hear "if I would be" in colloquial English and reproduce it in French. Standard French does not tolerate it. The rule is absolute: si never takes -rais.
❌ Si tu viendras demain, je serai content.
Incorrect — futur is forbidden in real conditional si-clauses; use the présent.
✅ Si tu viens demain, je serai content.
If you come tomorrow, I'll be happy.
The futur-in-the-future-clause error usually arises from confusion with quand-clauses, which do require the futur (quand tu viendras...). With si, real-conditional clauses always use the présent, even though the event is in the future. This contrast is one of the most-tested points at the B1 transition.
❌ Si j'aurais su, je serais venu.
Incorrect — conditionnel passé is forbidden in si-clauses; use the plus-que-parfait.
✅ Si j'avais su, je serais venu.
If I had known, I would have come.
A common variation of the -rais error in the past. The plus-que-parfait (j'avais su) is the only correct si-clause tense for Type 3.
❌ Si tu étudies plus, tu aurais réussi.
Incorrect — Type 1 si-clause cannot pair with conditionnel passé in the main clause.
✅ Si tu avais étudié plus, tu aurais réussi.
If you had studied more, you would have succeeded.
The tenses on the two sides of the conditional must form a valid pair. Type 1 main clauses are futur or présent, not conditionnel passé. To talk about a missed past success, you need the full Type 3 pattern: plus-que-parfait + conditionnel passé.
✅ Si je viens, est-ce que tu seras là ?
If I come, will you be there? — a correct Type 1 sentence learners often second-guess.
This last one is not an error, despite frequent learner doubt. Si je viens (présent) + tu seras là (futur) is the correct Type 1 pattern. There is no need to put the si-clause in the futur to "match" the future event — the rule is firm: the si-clause stays in the présent.
Key takeaways
The conditional system is one of the few corners of French grammar where the patterns are genuinely memorizable as templates. Once you know the three pairings, you can produce any conditional sentence you need — and you can spot conditional errors in your own writing instantly.
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Start learning French→Related Topics
- Les Subordonnées TemporellesB1 — How French expresses time relations in subordinate clauses — simultaneity, anteriority, and posteriority — with the conjunction-by-conjunction tense and mood requirements, including the avant que / après que asymmetry and the futur-after-quand rule that English speakers most need to unlearn.
- Le Conditionnel in Si-Clauses: Type 2, Type 3, and Mixed ConditionalsB1 — How the conditionnel pairs with the imparfait and plus-que-parfait to express counterfactual hypotheses about the present and the past — plus the mixed pattern, the universal English-speaker error to avoid, and the schoolyard rhyme that locks the rule in.
- L'Imparfait in Si-Clauses: Hypotheticals, Suggestions, and WishesB1 — How the imparfait pairs with the conditional to express counterfactual hypotheses, and how 'si + imparfait' alone proposes plans, regrets, and wishes.
- Plus-que-parfait in Si-Clauses: Past CounterfactualsB1 — The third type of French conditional pairs si + plus-que-parfait with the conditionnel passé to express what would have happened if the past had been different. Past unreal hypotheses about events that didn't actually occur.
- Never Use the Futur After Si: The Present-Tense Rule for ConditionalsB1 — The single rule that catches every English speaker: in real-condition sentences (Si tu viens, je serai content), the si-clause takes the present, never the futur. Plus the three-tier conditional system, the whether-exception, and a French mnemonic to lock it in.
- Pas de Conditionnel après 'si'B1 — The most stigmatized error in French: putting a conditional after 'si'. The rule is absolute — si never takes a conditional in the if-clause.