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B1 · Verb Tenses · Published
French Si Clauses
French si clauses pair an "if" clause with a result clause. The main rule is that French does not put the futur simple or the conditional directly after conditional si.
Si tu viens, on ira.
Instead, French uses three core tense ladders: present → future for likely conditions, imparfait → conditional for unlikely or imagined conditions, and plus-que-parfait → conditionnel passé for unreal past conditions. Learn those pairings and most si clauses become predictable.
This page covers the full practical system, including mixed conditions, si meaning "whether", a few higher-level hypothesis expressions such as au cas où, and an advanced note on literary or formal variations.
In short
- Likely future:
si+ present, result in future:si tu viens, on ira. - Unlikely or imagined present:
si+ imparfait, result in conditional:si tu avais le temps, tu viendrais. - Unreal past:
si+ plus-que-parfait, result in conditionnel passé:si j’avais su, je ne serais pas venu. - Do not put futur simple or conditional directly after conditional
si.
si clauseresult clauseother si / hypothesis expression· hover a highlighted word for its label
The three ladders of reality
Think of si clauses as three ladders. The first is still realistic. The second imagines a different present. The third is too late: it imagines a different past. Each ladder has a fixed tense pair.
| Meaning | Si-clause | Result clause |
|---|---|---|
| Real or likely future | si + present | future, imperative, or present |
| Imagined present | si + imparfait | conditional |
| Unreal past | si + plus-que-parfait | conditionnel passé |
Type 1: real or likely conditions
Use present tense after si when the condition is possible or likely. The result often uses the futur simple, but it can also be an imperative or a present-tense result.
The order can flip without changing the tenses:
Si tu viens, on ira.
On ira si tu viens.
si + present + futur simple
If you come, we will go to the market together.
— The condition is realistic: present after si, future in the result.
If you are hungry, take an apple.
— The result can be an imperative instead of a future.
If you want, we are leaving now.
— The result can also stay in the present.
Type 2: imagined present or unlikely future
Use imparfait after si when you imagine a different present or a less likely future. The result uses the present conditional. English often says "if I had..." or "if I were..." plus "would".
si + imparfait + conditional
If you had time, you could help me.
— Avais is imparfait; pourrais is conditional.
If I were mayor, I would create more bike lanes.
— French uses imparfait after si, even when English says "were".
Type 3: unreal past
Use plus-que-parfait after si when the condition did not happen in the past. The result uses the conditionnel passé: j’aurais fait, elle serait venue, nous aurions vu.
si + plus-que-parfait + conditionnel passé
If I had known, I would not have come.
— The knowing did not happen; the result did not happen either.
If the train had been on time, we would have seen the beginning.
— Plus-que-parfait in the si-clause; conditionnel passé in the result.
The golden rule: no future or conditional after si
When si means "if" and introduces a condition, the verb right after it is not futur simple and not conditional. This is the transfer error English speakers make most often because English allows "if you will" in some contexts and "if I would" in some dialects. French standard grammar does not.
Si tu viens, on partira.
Si tu venais, on partirait.
Si tu étais venu, on serait partis.
The result clause can use future, imperative, present, conditional, or conditionnel passé depending on the pattern. The restriction is on the verb inside the si-clause.
Mixed conditions
Sometimes the condition and the result live in different time frames. French still uses the same logic: choose the tense that fits each side.
If a past condition affects the present, use plus-que-parfait after si and present conditional in the result.
If a present condition affects the past in an imagined sentence, use imparfait after si and conditionnel passé in the result.
If you had booked, you would be sitting down now.
— Past condition, present result: plus-que-parfait plus present conditional.
If I were more organized, I would have sent the file yesterday.
— Present imagined trait, past unreal result.
When si means whether
Si does not always mean "if". After verbs like demander, savoir, or dire, it can mean "whether". In that case, the no-future-after-si rule does not apply in the same way, because this is not a condition.
I do not know whether she will come.
— Si means whether here, so future viendra is allowed.
Other hypothesis expressions
Two useful higher-level expressions appear often in formal French. Au cas où means "in case" and normally takes the conditional. À supposer que means "supposing that" and takes the subjunctive.
In case the bus is late, take a taxi.
— Au cas où is followed by the conditional serait.
Supposing that the project is accepted, we will start in September.
— À supposer que takes the subjunctive; the result can be future.
Advanced written variations
In formal writing, you may see inversions or literary alternatives around hypothesis: eût-il répondu or dans l’hypothèse où. At B1, do not try to produce them. Recognize that they are formal ways to build a condition, then translate the logic back to one of the three core ladders.
Common mistakes
✗Si tu viendras, on ira au marché.
✓Si tu viens, on ira au marché.
For a real future condition, French uses present tense after si, not futur simple.
✗Si j’aurais eu plus de temps, j’aurais fini.
✓Si j’avais eu plus de temps, j’aurais fini.
Unreal past conditions use plus-que-parfait after si; the conditionnel passé belongs in the result.
✗Si elle serait libre, elle nous aiderait.
✓Si elle était libre, elle nous aiderait.
Imagined present conditions use imparfait after si, not conditional.
✗Au cas où il pleut, prends un taxi.
✓Au cas où il pleuvrait, prends un taxi.
Au cas où normally takes the conditional, unlike conditional si.
Check yourself
1 / 4Si tu ___ demain, nous irons au musée. (venir)
2 / 4Si j’avais plus de temps, je ___ le rapport. (relire)
3 / 4Si nous avions su, nous ___ plus tôt. (partir)
4 / 4Je ne sais pas si elle ___ l’année prochaine. (venir)
Frequently asked questions
What are the three French si-clause patterns?
The core patterns are si + present → future, si + imparfait → conditional, and si + plus-que-parfait → conditionnel passé. The result can come before or after the si-clause.
Can I use the futur simple after si?
Not when si means "if" in a condition. Say si tu viens, on ira, not si tu viendras, on ira. If si means "whether", future forms can appear: je ne sais pas si elle viendra.
Can I use the conditional after si?
Not in the condition clause itself. Say si j’avais faim, je mangerais: imparfait after si, conditional in the result.
What is the difference between si and au cas où?
Conditional si uses present, imparfait, or plus-que-parfait depending on the type of condition. Au cas où means "in case" and normally takes the conditional: au cas où il pleuvrait.
Memory tip
Ask how real the condition is. Real future uses present; imagined present uses imparfait; too-late past uses plus-que-parfait.
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