Beyond who, what, which, and how much, Portuguese has a handful of question words for place, time, manner, and reason: onde / aonde (where), quando (when), como (how), and the famously tricky por que (why). Most are easy. Two of them hide real traps that even educated native speakers stumble over in writing — the onde / aonde distinction and the four-way por que / por quê / porque / porquê spelling puzzle. This page covers the simple ones quickly and the tricky ones thoroughly.
Onde vs aonde: static place vs movement toward
Both mean where, but they answer different questions. Onde asks about a static location — where something is. Aonde asks about a destination — where something is going. The a in aonde is the preposition a (to) fused on: aonde literally packs in the idea of to where.
Onde você mora?
Where do you live?
Onde fica o banheiro?
Where's the bathroom?
Aonde você vai?
Where are you going (to)?
Aonde a gente vai depois do trabalho?
Where are we going after work?
The rule of thumb: if the verb involves motion toward a place (ir, chegar, levar, vir), use aonde. If the verb describes being or staying somewhere (morar, ficar, estar, trabalhar), use onde. English collapses both into where, which is why learners default to onde everywhere and miss aonde.
A word of honesty: in casual speech many Brazilians use onde for everything, including with motion verbs, and you will be understood. But the onde / aonde distinction is real, it is taught in schools, and it is expected in careful or written Portuguese (formal). Learning it makes you sound more polished, and it costs almost nothing once you tie aonde to going.
De onde você é?
Where are you from?
Quando: when
Quando is wonderfully simple — it is invariable, takes no agreement, and maps cleanly onto English when. It can lead a question or follow a preposition.
Quando você chega?
When do you arrive?
Até quando você vai ficar?
Until when are you staying? / How long are you staying for?
Desde quando isso tá acontecendo?
Since when has this been happening?
As with quem, prepositions go in front: até quando, desde quando, para quando (Para quando é a prova? — When is the test for?). No surprises beyond that.
Como: how (and "what?" / "pardon?")
Como means how, and it is also invariable.
Como você fez isso?
How did you do that?
Como se diz 'saudade' em inglês?
How do you say 'saudade' in English?
But como has a second job that surprises English speakers: on its own, Como? means What? / Sorry? / Pardon? — it is the polite way to ask someone to repeat themselves. English uses what? for this; Portuguese prefers Como? (using O quê? for what? in this sense can sound a bit blunt or surprised).
Como? Não escutei direito.
Sorry? I didn't quite hear you.
Como assim?
What do you mean? / How so?
The por que quartet: the top spelling trap in Portuguese
Here is the part that genuinely confuses native speakers. Portuguese has four ways to write porque-ish words, and each has a distinct job. Mixing them up is one of the most common writing errors in the language. There is no shortcut — you have to learn the four roles.
| Form | Role | Translation | Position |
|---|---|---|---|
| por que | asking why (question) | why | start/middle of a question |
| por quê | asking why (question) | why | end of a sentence (stressed) |
| porque | giving a reason (answer) | because | introducing the cause |
| porquê | the reason itself (noun) | the reason / the why | after an article: o porquê |
1. por que (two words) — asking why
When you ask a why question and the sentence continues after it, use por que, written as two separate words.
Por que você não veio ontem?
Why didn't you come yesterday?
Por que o céu é azul?
Why is the sky blue?
2. por quê (two words, accented) — why at the end
When the why lands at the very end of the sentence — or stands alone — it gets a circumflex: por quê. Same reason as o quê: a stressed word in final position is marked with the accent.
Você não vem? Por quê?
You're not coming? Why?
Ela foi embora, e eu nem sei por quê.
She left, and I don't even know why.
3. porque (one word) — because (the answer)
When you give the reason, use porque, written as one word, unstressed. This is the because that answers a por que question.
Não vim porque estava doente.
I didn't come because I was sick.
— Por que você tá rindo? — Porque você é engraçado.
— Why are you laughing? — Because you're funny.
4. porquê (one word, accented) — the reason (a noun)
When the word becomes a noun meaning the reason / the why, it is one word with a circumflex: porquê. It is preceded by an article or determiner (o porquê, um porquê) and can even be pluralized (os porquês).
Eu quero entender o porquê dessa decisão.
I want to understand the reason for this decision.
Ela tem os seus porquês.
She has her reasons.
The underlying logic helps: the question forms stay as two words (por que / por quê), because they are still the preposition por + the question word que. The answer and the noun have fused into one word (porque / porquê) — they have become single lexical items. And the accent (quê / porquê) marks stress at the end or in the noun, just as it does in o quê.
Quick reference
| Word | Meaning | Example |
|---|---|---|
| onde | where (static) | Onde você mora? |
| aonde | where to (motion) | Aonde você vai? |
| de onde | where from | De onde você é? |
| quando | when | Quando começa? |
| como | how / pardon? | Como funciona? |
| por que | why (question) | Por que não? |
| por quê | why (final) | Por quê? |
| porque | because (answer) | ...porque sim. |
| o porquê | the reason (noun) | o porquê disso |
Common Mistakes
❌ Onde você vai?
Debatable — careful Portuguese wants aonde with a motion verb
✅ Aonde você vai?
Where are you going?
With ir (motion toward), careful and written Portuguese uses aonde. Onde você vai is widespread in casual speech but is corrected in school and formal writing.
❌ Porque você não veio?
Incorrect — a question needs the two-word por que
✅ Por que você não veio?
Why didn't you come?
A why question is por que (two words). One-word porque means because and answers the question.
❌ Você não vem? Por que?
Incorrect — sentence-final why needs the accent
✅ Você não vem? Por quê?
You're not coming? Why?
At the end of the sentence the word is stressed: por quê, with a circumflex.
❌ Não fui por que estava cansado.
Incorrect — the reason (because) is one word, no accent
✅ Não fui porque estava cansado.
I didn't go because I was tired.
Giving a reason uses the single word porque with no accent.
❌ Quero saber o por que disso.
Incorrect — the noun 'the reason' is one accented word
✅ Quero saber o porquê disso.
I want to know the reason for this.
After an article (o), the noun form is one word with a circumflex: o porquê.
Key Takeaways
- Onde (static) vs aonde (motion toward); de onde for where from.
- Quando and como are invariable; Como? alone means Pardon?
- The quartet: Por que? (question, 2 words) / Por quê? (final, accented) / porque (because, 1 word) / o porquê (the reason, accented noun).
- Questions stay two words; the answer and the noun fuse into one — and the accent marks final/noun stress.
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Start learning Portuguese→Related Topics
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- Interrogative Quanto / Quanta / Quantos / Quantas: How Much/ManyA1 — Asking 'how much' and 'how many' in Brazilian Portuguese with quanto and its agreeing forms, plus prices and age.
- Onde vs Aonde (Where vs Where To)A1 — How to ask 'where' in Brazilian Portuguese, and why aonde, de onde, and por onde each pair with a different kind of verb.
- Por Que / Porque / Porquê / Por Quê: Four FormsA2 — The famous four porquês of Brazilian Portuguese explained with one clean rule — separated vs joined, accented vs unaccented — and a full decision table.
- Como (How)A1 — How to use 'como' in Brazilian Portuguese — asking how, the polite 'Como?' for repetition, como assim, como é que, and its life as a comparison and cause conjunction.