what is it?
Spanish uses three closely related forms to talk about reasons and purposes. Porque (one word, unstressed) means "because" and introduces a cause, followed by a conjugated verb. Para + infinitive means "in order to" and states a purpose, always followed by the bare infinitive. Por qué (two words, stressed qué) means "why" and is used in direct questions and in reported questions. The three forms look similar but serve entirely different functions.
when to use it
porque — use it to give a reason or cause. It connects two clauses: the result comes first, the cause follows. The verb after porque is always conjugated: No voy porque estoy cansado.
para + infinitive — use it to express the goal or purpose of an action when the subject of both verbs is the same person. The verb after para must be an infinitive: Estudio para aprender.
por qué — use it to ask "why" in a direct question, or to report a question about a reason (e.g. after no sé…, pregunto…). It is always written as two words and carries a written accent on qué.
formation
The three forms have fixed structures. The table below shows each pattern with a short example.
| form | structure | example |
|---|---|---|
| porque | clause + porque + conjugated verb | No voy porque estoy cansado. |
| para + infinitive | verb + para + infinitive | Estudio español para viajar. |
| por qué | ¿Por qué + conjugated verb…? | ¿Por qué llegas tarde? |
Spelling summary: porque = one word, no accent (gives a reason). por qué = two words, accent on qué (asks or reports why). para = one word, always followed by an infinitive (states a purpose).
examples in context
common pitfalls
para followed by a conjugated verb. When the subject is the same in both clauses, the verb after para must be an infinitive. ✗ estudio español para viajo a México → ✓ estudio español para viajar a México.
Using para + infinitive to express a cause. Para expresses purpose (a goal), not a cause (a reason). To give a reason, use porque with a conjugated verb. ✗ estoy cansado para trabajar mucho → ✓ estoy cansado porque trabajo mucho.
Writing por qué as one word in questions and reported questions. When asking or reporting why, the form is always two words with an accent: por qué. ✗ no sé porque llegas tarde → ✓ no sé por qué llegas tarde. The one-word form porque only introduces a cause, never a question.