Qué often asks for a definition or accompanies a noun: ¿Qué es esto? means “What is this?” and ¿Qué libro lees? means “What book are you reading?” Cuál often identifies a choice: ¿Cuál prefieres? means “Which one do you prefer?” These are useful starting patterns, but English “what” and “which” do not map onto the Spanish words perfectly. Learn common question shapes and consider the answer you expect.
Use qué to ask what something is or means
¿Qué es una biblioteca? asks “What is a library?” You expect a definition or explanation. ¿Qué significa esta palabra? means “What does this word mean?” ¿Qué haces? asks what someone does or is doing. None of these questions requires a visible menu of choices.
A useful answer to ¿Qué es esto? might be Es una herramienta, “It is a tool.” You are classifying the object, rather than selecting its identity from a known set. The pattern is a helpful starting point, not a claim that every question beginning qué es has exactly the same conversational purpose.
Use cuál to identify a person or thing among possibilities
If two cups are on the table, ¿Cuál es tu taza? asks “Which one is your cup?” ¿Cuál prefieres? asks which one you prefer. The options can be understood without being directly in front of you: ¿Cuál es tu película favorita?, “What is your favorite movie?”
This explains a familiar question: ¿Cuál es tu nombre?, “What is your name?” The expected answer is your particular name, not a definition of the word nombre. You can also ask ¿Cómo te llamas?. Memorize the useful complete question instead of forcing a word-for-word match with English “what.”
Qué plus a noun is a reliable starting pattern
¿Qué libro quieres? means “What book do you want?” or “Which book do you want?” ¿Qué idioma estudias? means “What language are you studying?” Qué before a noun is widely useful, even when English prefers “which.”
You may also hear ¿Cuál libro quieres? in American Spanish. This use of cuál directly before a noun is recognized and is more frequent in the Americas than in Spain. Do not assume it is universally wrong. As a learner, ¿Qué libro…? is a dependable starting choice; recognize the alternative when people around you use it. Regional variation changes your listening task as well as your speaking choices.
Use cuáles for several choices; keep qué unchanged
Cuál has a plural: cuáles. Compare ¿Cuál necesitas? (which one do you need?) and ¿Cuáles necesitas? (which ones do you need?). Neither has a separate masculine or feminine form. Qué stays unchanged: ¿Qué libros necesitas?, “What books do you need?”
To make a set explicit, use cuál de or cuáles de: ¿Cuál de estas rutas es más corta?, “Which of these routes is shorter?” Prepositions can come first: ¿Con cuál te quedas?, “Which one are you keeping?” Practice the whole phrase so you keep the relationship expressed by the preposition.
Keep accents in indirect questions too
The interrogative words qué, cuál, and cuáles take written accents in these question uses. This also applies when a question is embedded in a statement: No sé qué quieres (I do not know what you want); Dime cuál prefieres (tell me which one you prefer). The absence of question marks does not remove their interrogative meaning.
Compare El libro que quiero está aquí, “The book that I want is here.” That unaccented que links a description to libro. Rather than memorizing “questions have accents” as a punctuation rule, ask whether the word introduces the unknown information. It can do that inside a sentence ending in a period.
Practice with the answer in mind
Choose the most useful pattern for the intended question. 1. What is this object? ¿___ es esto? 2. Which of these shirts do you prefer? ¿___ de estas camisas prefieres? 3. What books are you reading? ¿___ libros lees? 4. Which ones do you want? ¿___ quieres? 5. I do not know which one is yours: No sé ___ es el tuyo.
Show answers
1. Qué: identify or explain the object. 2. Cuál: select from an explicit set. 3. Qué: directly before libros. 4. Cuáles: plural choices. 5. cuál: an indirect question, with its accent.
Make one definition question and one selection question about things nearby. Answer each aloud. The answer you expect helps the distinction become concrete.
Sources & further reading
Our examples and explanations are written for LSFR learners. These references provide further detail.