A causal clause answers the question why? In French, causal subordinators come in a small but stylistically rich set, each carrying its own register and its own discourse function. The grammar is simple — all causal subordinators take the indicative — but the choice between them is one of the most expressive registers in French. Parce que, car, puisque, and comme all translate as "because" or "since" in English, but they are very far from interchangeable.
This page walks through the seven main causal subordinators, the two prepositions à cause de and grâce à (which connect a cause to a noun phrase rather than a clause), and the high-frequency English-to-French calque mistakes around "because of." Once you internalize the discourse logic — what the speaker is doing with the cause, not just that there is one — choosing the right marker becomes intuitive.
All causal subordinators take the indicative
Lock this in first. Unlike anteriority (avant que, jusqu'à ce que) or concession (bien que, quoique), causal subordinators never trigger the subjunctive. The cause is presented as a fact, so the indicative is the natural mood.
Je ne viens pas parce que je suis fatigué.
I'm not coming because I'm tired.
Comme il pleuvait, on est restés à la maison.
Since it was raining, we stayed home.
Puisque tu es là, aide-moi à porter ça.
Since you're here, help me carry this.
There is no causal conjunction that takes the subjunctive. If you ever feel tempted to write parce qu'il soit fatigué, that is a transfer error from the concessive bien que — stop and switch to the indicative.
Parce que — the default, the workhorse
Parce que is the most common causal conjunction in French. It is neutral in register, works in any position in the sentence, and can answer the explicit question pourquoi ?. If you don't know which to use, use parce que.
Je ne suis pas venue à la fête parce que j'avais trop de travail.
I didn't come to the party because I had too much work.
Pourquoi tu ne manges pas ? — Parce que je n'ai pas faim.
Why aren't you eating? — Because I'm not hungry.
Parce que je te le dis.
Because I say so.
Parce que is the only French causal conjunction that can stand alone as the answer to pourquoi ?. You cannot answer pourquoi ? with car, puisque, or comme.
Car — formal, written, never sentence-initial
Car is the literary and formal cousin of parce que. It belongs primarily to writing and to elevated speech (newscasts, lectures, essays). In casual conversation, car sounds bookish.
A non-negotiable rule: car cannot start a sentence. It is a coordinating conjunction (treated grammatically like et, mais, ou), and like those it must follow another clause.
Je dois partir, car il est déjà tard.
I must leave, for it's already late.
L'expérience a été abandonnée, car les résultats étaient insuffisants.
The experiment was abandoned, for the results were inadequate. (academic)
Il n'a pas pu venir, car son train avait été annulé.
He couldn't come, for his train had been cancelled. (formal)
The closest English equivalent is "for" in the formal/literary sense — He stayed home, for he was tired. Both languages reserve this register for writing or self-consciously elevated speech. In everyday French, parce que covers exactly the same semantic ground.
Puisque — the cause is shared knowledge
Puisque introduces a cause that is already known to both speaker and listener — or that the speaker is treating as obviously true, as common ground. The reasoning structure is: given that we both know X, the consequence Y follows.
Puisque tu es là, on peut commencer la réunion.
Since you're here, we can start the meeting.
Puisque tu insistes, je veux bien rester un peu plus longtemps.
Since you insist, I'll stay a bit longer.
Puisqu'il faut le dire, c'est moi qui ai cassé le vase.
Since it has to be said, I'm the one who broke the vase.
The crucial nuance: with parce que, the cause is new information for the listener; with puisque, the cause is presupposed — old, shared, or obvious. Compare:
Je pars parce qu'il est tard.
I'm leaving because it's late. (informing you that it's late)
Puisqu'il est tard, je pars.
Since it's late (as we both can see), I'm leaving.
The first sentence introduces il est tard as a reason. The second takes il est tard as already established and uses it as a basis for the decision to leave. Puisque implies "you already know this, so I'm using it as a premise."
This explains why puisque often feels argumentative or insistent — it presents the cause as inarguable: puisque tu insistes (since you're insisting — and we both know it). It can sometimes carry a faint reproach.
Comme — sentence-initial, presentational
Comme in causal use is almost always sentence-initial. It introduces the cause as background information, setting up the scene before the main clause delivers the consequence. It is a presentational device.
Comme il pleut, je reste à la maison.
As it's raining, I'm staying home.
Comme tu n'avais pas répondu à mon message, je suis venu directement.
Since you hadn't replied to my message, I came directly.
Comme il faisait froid ce matin-là, j'ai pris mon manteau.
As it was cold that morning, I took my coat.
You can think of comme as the sentence-opener that frames a cause first. Once you've stated the cause with comme, the main clause delivers the result. Reversing the order — putting comme mid-sentence — is not idiomatic in causal use. Je reste à la maison comme il pleut sounds wrong.
Comme and puisque overlap in some uses but differ in emphasis: comme simply establishes background; puisque asserts that the cause is already known and uses it as a premise.
Du fait que, étant donné que, vu que — formal "given that, seeing that"
These are heavier, more formal causal subordinators, common in administrative, journalistic, and academic French. They explicitly frame the cause as a stated premise, often used to introduce reasoning.
Du fait qu'il est absent, la réunion est reportée.
Given that he is absent, the meeting is postponed.
Étant donné que la situation a évolué, nous devons revoir notre stratégie.
Given that the situation has changed, we need to revise our strategy. (formal)
Vu que c'est dimanche, tous les magasins sont fermés.
Seeing as it's Sunday, all the shops are closed.
Étant donné que and du fait que belong to formal/written register. Vu que is more casual — the colloquial cousin of étant donné que, common in spoken French.
If you are texting a friend, use parce que or vu que; in a report or essay, étant donné que fits naturally.
Sous prétexte que — "on the pretext that"
Sous prétexte que introduces a cause that the speaker considers false, weak, or insincere. It is the marker of skepticism: the speaker is reporting someone else's stated reason while signaling that they don't believe it.
Il a refusé de venir sous prétexte qu'il était malade.
He refused to come on the pretext that he was sick. (we don't believe him)
Elle a quitté la réunion sous prétexte qu'elle avait un autre rendez-vous.
She left the meeting on the pretext that she had another appointment. (we suspect she didn't)
Sous prétexte que c'est dimanche, tu refuses de m'aider ?
On the pretext that it's Sunday, you're refusing to help me?
Use sous prétexte que with care — it explicitly accuses the other person of giving a false reason. In casual conversation it can sound confrontational, but in journalism and analysis it is a precise marker of reported, doubtful causation.
"Because of" — à cause de vs grâce à
When the cause is a noun phrase rather than a clause, French uses prepositions, not conjunctions. The two main ones are à cause de and grâce à, and the choice between them depends on whether the cause is bad or good.
À cause de — negative or neutral
À cause de attributes a cause, often with a negative or neutral-but-blameworthy connotation. It is the default for assigning cause to an undesirable outcome.
On est arrivés en retard à cause des embouteillages.
We arrived late because of the traffic jams.
Le match a été annulé à cause de la pluie.
The match was cancelled because of the rain.
C'est à cause de toi que j'ai raté mon train.
It's because of you that I missed my train. (blaming)
When à cause de refers to a person, it almost always carries a hint of blame — à cause de toi tends to mean "you're responsible for this bad thing." For a positive attribution to a person, French switches to grâce à.
Grâce à — positive
Grâce à attributes a cause with a positive connotation. The literal meaning is "thanks to," and that is exactly the discourse function: the cause is appreciated, credited, or beneficial.
Grâce à toi, j'ai réussi mon examen.
Thanks to you, I passed my exam.
Grâce à cette nouvelle technologie, on peut travailler de chez soi.
Thanks to this new technology, we can work from home.
C'est grâce à mes parents que j'ai pu faire ces études.
It's thanks to my parents that I was able to do these studies.
The contrast is sharp and worth practicing on the same person:
À cause de mon frère, j'ai été puni.
Because of my brother (who got me into trouble), I was punished.
Grâce à mon frère, j'ai trouvé du travail.
Thanks to my brother (who helped me), I found a job.
Both sentences attribute the outcome to the brother; only the moral evaluation differs.
En raison de — formal, neutral
En raison de is the formal, register-neutral equivalent of à cause de. It carries no negative connotation and is preferred in administrative or journalistic writing.
En raison de travaux, la ligne 4 est interrompue.
Due to engineering works, line 4 is suspended.
L'événement a été reporté en raison du mauvais temps.
The event has been postponed due to bad weather.
In notices, official communications, and news reports, en raison de replaces à cause de for neutral facts.
Summary table
| Marker | Type | Register | Discourse role |
|---|---|---|---|
| parce que | conjunction | neutral | introduces a cause as new information |
| car | conjunction (coord.) | formal / written | elevated 'for', never sentence-initial |
| puisque | conjunction | neutral | cause is presupposed / shared knowledge |
| comme | conjunction | neutral | presentational, sentence-initial |
| du fait que | conjunction | formal | 'given that' (formal premise) |
| étant donné que | conjunction | formal / academic | 'given that' (academic premise) |
| vu que | conjunction | informal | 'seeing that' (casual) |
| sous prétexte que | conjunction | neutral | cause is false / suspect |
| à cause de | preposition + nom | neutral / negative | blameworthy or undesirable cause |
| grâce à | preposition + nom | positive | credit, beneficial cause |
| en raison de | preposition + nom | formal / neutral | neutral cause (admin / news) |
All clausal markers take the indicative.
Common Mistakes
❌ Car il est tard, je pars.
Incorrect — 'car' cannot start a sentence.
✅ Je pars, car il est tard.
I'm leaving, for it's late.
Car is a coordinating conjunction. Like et, mais, and ou, it must follow another clause. To begin a sentence with the cause in formal writing, use comme or étant donné que instead.
❌ Pourquoi tu pars ? — Car il est tard.
Incorrect — 'car' cannot stand alone as the answer to 'pourquoi'.
✅ Pourquoi tu pars ? — Parce qu'il est tard.
Why are you leaving? — Because it's late.
Only parce que can answer pourquoi ? in isolation. Car, puisque, comme, and the others all need to be embedded in a fuller sentence — they introduce a cause within a discourse, but they cannot be the cause-as-answer the way parce que can.
❌ Grâce à la pluie, le match a été annulé.
Awkward — 'grâce à' for an undesirable outcome creates an unintended ironic effect.
✅ À cause de la pluie, le match a été annulé.
Because of the rain, the match was cancelled.
Grâce à always implies that the cause is welcome. Using it for an undesirable outcome (a cancellation, a delay, a problem) sounds either ironic or wrong. For undesirable outcomes, use à cause de (neutral or negative) or en raison de (formal-neutral).
❌ Parce que il est tard, je pars.
Incorrect — 'parce que' elides before a vowel: 'parce qu'il'.
✅ Parce qu'il est tard, je pars.
Because it's late, I'm leaving.
The e of que always drops before a vowel: parce qu'il, parce qu'on, parce qu'elle, parce qu'aujourd'hui. Likewise: puisqu'il, puisqu'on, lorsqu'il. This is automatic in French and any other spelling is wrong.
❌ Parce de la pluie, on rentre.
Incorrect — 'parce que' is a conjunction (+ clause). For 'because of + noun', use 'à cause de' or 'en raison de'.
✅ À cause de la pluie, on rentre.
Because of the rain, we're going home.
This is the most frequent transfer error from English. English uses because (+ clause) and because of (+ noun) — two forms of the same word. French uses two completely different words: parce que (+ clause), à cause de (+ noun). They are not interchangeable.
Key takeaways
Choosing the right causal marker is one of the clearest registers of fluency in French. Native speakers detect immediately when a learner uses parce que in a formal essay (sounds spoken-register) or car in a text message (sounds bookish).
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