Porque vs Por que vs Porquê (Why) | Portuguese (Portugal) Grammar

English uses a single word — why — both to ask a question ("Why did you do that?") and to answer one ("Because I wanted to"). Portuguese uses four: porque, por que, porquê, and por quê. They sound nearly identical, and the spelling distinctions are where learners (and even native speakers) trip up. This page maps out which form goes where, why the distinction matters, and where PT-PT usage honestly diverges from what Brazilian textbooks teach.

The core insight: Portuguese separates the question from the answer in writing. The question form wants an accent somewhere. The answer form — the causal conjunction porque — does not. Once you see it as "the word with the accent or the space is the question, the one without is the answer," most of the system falls into place.

The four forms at a glance

Form	Written as	Function	Position	Example
porque	one word, no accent	conjunction ("because")	introduces a cause clause	Fiquei em casa porque estava a chover.
por que	two words, no accent	interrogative ("why") / relative ("for which")	start or middle of a question	Por que razão fizeste isso?
porquê	one word, with accent	noun ("the reason") / stressed question word	end of question, or with article	Quero saber o porquê.
por quê	two words, with accent	stressed interrogative ("why")	end of question, before punctuation	Fizeste isso por quê?

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Think of the accent as a stress mark. When the "why-word" lands at the end of a sentence (or stands alone as a fragment), Portuguese needs the accent — porquê or por quê — because the syllable is stressed in speech. When it sits mid-sentence in a question, the accent is unnecessary — por que. And when it links two clauses as a conjunction, it is unstressed — just plain porque.

Porque — the causal conjunction

Porque (one word, no accent) is by far the most common of the four. It is the equivalent of English because. It joins a main clause to a cause clause — the reason, the motive, the justification.

Fiquei em casa porque estava a chover.

I stayed home because it was raining.

Ela não veio à festa porque tem muito trabalho.

She didn't come to the party because she has a lot of work.

Estou contente porque me deram a bolsa.

I'm happy because they gave me the scholarship.

Não te disse nada porque não queria preocupar-te.

I didn't tell you anything because I didn't want to worry you.

This porque is never stressed in speech, which is why there is no accent. The stress in the sentence falls on the main verb or the content of the cause clause, not on porque itself. In the International Phonetic Alphabet, it is typically [puɾ'kɨ] in PT-PT — the final vowel is reduced almost to silence.

Porque at the start of a sentence (answering a why)

In spoken Portuguese, porque also appears at the very beginning of a standalone sentence — as a freestanding answer to a why question. This is identical to English "Because..." as a reply.

— Porque é que não comeste? — Porque não tinha fome.

'Why didn't you eat?' 'Because I wasn't hungry.'

— Não vais? — Porque não me apetece.

'You're not going?' 'Because I don't feel like it.'

Por que — the interrogative (and the relative)

Por que (two words, no accent) has two distinct jobs, both of them mid-sentence.

Job 1: interrogative "why" at the start of a question

This is the form many grammar books identify as the "standard" written interrogative. It is a contraction of por (for) + que (what) — literally "for what (reason)."

Por que motivo chegaste tão tarde?

For what reason did you arrive so late?

Por que razão decidiu mudar de emprego?

For what reason did he decide to change jobs?

When the word motivo or razão is elided (which is almost always, in real speech), you get the bare form:

Por que fizeste isso?

Why did you do that?

Por que é que não me ligaste ontem?

Why didn't you call me yesterday?

Notice the é que reinforcement in the second example. This construction — por que é que... — is one of the most characteristic features of European Portuguese interrogatives. It is not mandatory, but it is so common in spoken PT-PT that omitting it often sounds clipped or overly formal. É que is a kind of emphatic filler that makes the question flow naturally; it has no direct equivalent in English translation.

Job 2: relative "for which"

Por que also appears inside a relative clause meaning "for which" or "through which." Here the que is a genuine relative pronoun.

Essas são as razões por que não compareci.

Those are the reasons for which I didn't show up. (formal/literary)

A cidade por que passámos era linda.

The city through which we passed was lovely. (literary)

This usage is (literary) — in everyday PT-PT, you are far more likely to hear pelas quais or por onde. But you will encounter it in news articles and formal writing, so recognizing it matters.

Porquê — the noun and the end-of-sentence question word

Porquê (one word, with the circumflex accent) is the stressed form. It has two uses.

Job 1: the noun meaning "the reason" / "the why"

With a definite article, porquê becomes a full noun — "the why," "the reason." You can even pluralize it (os porquês).

Ainda não percebi o porquê da decisão.

I still haven't understood the reason for the decision.

Os miúdos andam sempre a perguntar porquês.

Kids are always asking whys.

Ela quer saber o porquê de tanta pressa.

She wants to know the reason for such a hurry.

This is an extremely useful construction — it lets you talk about the reason as a thing without having to build a longer a razão pela qual phrasing.

Job 2: the stressed question word — "Why?" as a fragment or at the end

When why stands completely alone as a question, or appears at the very end of a sentence where the stress naturally falls on it, PT-PT writes porquê.

— Vou desistir do curso. — Porquê?

'I'm going to drop out of the course.' 'Why?'

Ele fez isso porquê?

He did that why?

Não percebo porquê.

I don't understand why.

The fragment Porquê? — used alone as a reaction — is one of the most frequent little words in PT-PT conversation. Beginners should learn it as a unit.

Por quê — the separated stressed form

Por quê (two words, with the accent) is the least common of the four in PT-PT and the one most grammar books treat as optional. It appears at the end of a sentence, before a period, question mark, or comma, when the speaker wants to emphasize the interrogative separately.

Fizeste isso por quê?

You did that why? (emphatic, somewhat colloquial)

Ela saiu cedo, por quê?

She left early — why?

Honest note on usage: Many PT-PT writers simply use porquê in this position instead, and most style guides accept both. If you are uncertain, prefer porquê (one word) at the end of a sentence — it is the more common choice in contemporary PT-PT. Por quê is more alive in Brazilian written usage.

The PT-PT vs PT-BR honest split

Brazilian grammar prescriptions are strict: por que (two words) for interrogatives at the start of a sentence, porque (one word) only for the causal conjunction. Under this rule, "Por que fizeste isso?" is correct and "Porque fizeste isso?" is an error.

European Portuguese is more relaxed. In PT-PT, you will regularly see Porque (one word) at the start of an interrogative, especially in everyday writing — newspaper headlines, WhatsApp messages, informal blog posts.

Porque não me disseste nada?

Why didn't you tell me anything? (PT-PT common written usage)

Por que não me disseste nada?

Why didn't you tell me anything? (PT-PT formal / PT-BR standard)

Both are understood and both appear in print in Portugal. The Acordo Ortográfico does not force one over the other for this case. If you are writing a formal document, exam, or academic text in PT-PT, use por que (two words) for the interrogative — it is never wrong. In informal PT-PT writing, porque (one word) is extremely common and not considered a mistake by most native speakers.

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For safe, register-neutral PT-PT writing: use por que (two words) to start a question, porque (one word) for "because," porquê (one word, accented) at the end of a question or as a noun. These three cover 95% of real usage. Save por quê for when you really want that separated, emphatic end-of-sentence feel — and know that most PT-PT readers would not flinch if you wrote porquê instead.

The "é que" reinforcement pattern

One reason PT-PT speakers feel comfortable writing Porque at the start of interrogatives is that the é que construction effectively absorbs the interrogative force. Porque é que fizeste isso? is not ambiguous — the é que marks it clearly as a question, no matter how you spell the first word.

Porque é que chegaste tarde?

Why did you arrive late?

Por que é que ninguém me avisou?

Why did nobody warn me?

Porquê é que ele está a chorar?

Incorrect — porquê with the accent does not combine with é que; use porque or por que

The third example is wrong because the stressed porquê cannot sit before é que. The unstressed form — porque or por que — is what the é que construction expects.

Comparison with English

English collapses all four Portuguese forms into one: why. When you translate from English into Portuguese, you must therefore stop and ask:

Is this joining a cause clause? ("I stayed home because it was raining.") → porque
Is this starting a direct question? ("Why did you do that?") → por que / porque
Is this the noun 'the reason'? ("She asked the why of it.") → o porquê
Is this a standalone 'Why?' or 'Why?' at the end? → Porquê?

English speakers also have to absorb a purely orthographic fact: Portuguese distinguishes porque (unstressed, because) from porquê (stressed, why) with a single accent. A missing accent is not a typo — it is a different word.

Quick decision flow

Ask yourself	If yes	Write
Does the word introduce a reason ("because...")?	Yes	porque (one word, no accent)
Is it a question starting mid-sentence with "for what reason"?	Yes	por que (two words) — or porque in informal PT-PT
Does the word stand alone as "Why?" or end a question?	Yes	porquê (one word, with accent)
Is the word used as a noun ("the reason")?	Yes	o porquê (one word, with accent, with article)
Is it a separated, stressed question form at the end?	Yes, and you want the emphasis	por quê (two words, with accent) — rare in PT-PT, prefer porquê

Common mistakes

❌ Fiquei em casa por que estava a chover.

Incorrect — the causal conjunction is one word, no accent

✅ Fiquei em casa porque estava a chover.

I stayed home because it was raining.

❌ Porque?

Incorrect as a standalone question — the stressed standalone form needs the accent

✅ Porquê?

Why?

❌ Quero saber o porque da decisão.

Incorrect — as a noun, the word requires the accent

✅ Quero saber o porquê da decisão.

I want to know the reason for the decision.

❌ Porquê é que chegaste tarde?

Incorrect — before é que, use the unstressed form

✅ Porque é que chegaste tarde? / Por que é que chegaste tarde?

Why did you arrive late?

Não sei por que ele fez isso.

I don't know why he did that. (formal PT-PT; acceptable but slightly stiff)

Não sei porque ele fez isso.

I don't know why he did that. (colloquial PT-PT preference in indirect questions)

Não sei porquê — ele fez isso sem motivo.

I don't know why — he did it for no reason. (standalone porquê at the clause end)

Key takeaways

porque (one word, no accent): causal conjunction — "because." Also widely used in PT-PT at the start of interrogatives, despite stricter Brazilian prescriptions.
por que (two words, no accent): interrogative at the start of a question, especially in formal PT-PT; also a relative pronoun meaning "for which" (literary).
porquê (one word, with accent): the stressed form — used at the end of questions, as a standalone "Why?", or as a noun meaning "the reason."
por quê (two words, with accent): rare in PT-PT; occasionally used for emphatic end-of-sentence questions. Most PT-PT writers prefer porquê in this position.
The é que pattern — Porque é que..., Por que é que... — is the natural spoken rhythm of PT-PT wh-questions and welcomes either spelling of the first word.
The accent is not decorative — it marks the stressed vowel and distinguishes the stressed forms (porquê, por quê) from the unstressed ones (porque, por que).