Infinitive vs. 'que' + subjunctive (literally: Infinitive vs. 'that' + subjunctive) - Spanish Grammar

Infinitive vs. que + subjunctive in Spanish — What it means and when to use each

Spanish often gives you two ways to say that one action depends on another: use an infinitive (e.g., "esperar + infinitive") or use a subordinate clause introduced by que + the subjunctive ("esperar que + subjunctive"). The main difference is usually about who does the action (the subject) and about the attitude of the speaker (wish, request, doubt, necessity, emotion).

The simplest rule: same subject → infinitive; different subject → que + subjunctive

Same subject: use the infinitive

If the subject of the main clause and the action expressed after it is the same person, use the infinitive.

Spanish: "Espero terminar el informe hoy." — English: "I hope to finish the report today." (Subject: I / yo in both parts.)
Spanish: "Necesito dormir." — English: "I need to sleep." (Same subject.)
Spanish: "Quiero aprender español." — English: "I want to learn Spanish." (Same subject.)

Different subject: use que + subjunctive

If the second action has a different subject, introduce a clause with que and use the subjunctive.

Spanish: "Espero que termines el informe hoy." — English: "I hope that you finish the report today." (Main subject: I; subordinate subject: you.)
Spanish: "Necesito que vengas ahora." — English: "I need you to come now." (Different subject.)
Spanish: "Quiero que ellos estudien más." — English: "I want them to study more." (Different subject.)

When to use the infinitive: common situations

After a verb when the subject does not change

"Voy a salir." — "I am going to leave."
"Esperamos encontrar una solución." — "We hope to find a solution." (Esperamos + infinitive because same subject.)

After prepositions

Infinitives follow prepositions: para, sin, antes de, después de, al, etc.

"Antes de salir, cierra la ventana." — "Before leaving, close the window."
"Sin decir nada, se fue." — "Without saying anything, he left."

After impersonal, general statements (no specific subject)
When you give general advice or state facts, the infinitive is common.

"Es importante estudiar." — "It is important to study." (General statement.)

"Es fácil equivocarse." — "It is easy to make a mistake."

After verbs of perception or with modal verbs

"La vi entrar." — "I saw her enter."
"Tengo que terminar." — "I have to finish."

When to use que + subjunctive: common situations

When the subordinate clause has its own subject (main rule)
You need que + subjunctive whenever the subordinate clause has a different subject from the main clause.

"Te pido que me escuches." — "I ask you to listen to me." (I / you)

After verbs of will, influence, requests, commands, emotions, doubt, or denial

These categories trigger the subjunctive in subordinate clauses.

Wishes/requests: "Quiero que vengas." — "I want you to come."
Requests/orders: "Le pedí que abriera la puerta." — "I asked him to open the door." (past)
Emotions: "Me alegra que estés aquí." — "I’m glad that you are here."
Doubt/denial: "Dudo que venga mañana." — "I doubt that he will come tomorrow."

After impersonal expressions that address necessity/opinion about a person
When an impersonal expression points to a specific person or situation, use que + subjunctive.

"Es necesario que firmes esto." — "It’s necessary that you sign this."

Compare: "Es necesario firmar documentos." — "It’s necessary to sign documents." (general)

After conjunctions that require the subjunctive

Common ones: para que, antes de que, a menos que, con tal de que, en caso de que.

"Estudia para que puedas aprobar." — "Study so that you can pass." (para que + subjunctive)
"No salgas a menos que te lo pidan." — "Don’t go out unless they ask you to." (a menos que + subjunctive)

Examples with esperar, pedir, necesitar (the verbs you asked about)

Esperar
- Infinitive (same subject): "Espero ver la película esta noche." — "I hope to see the movie tonight." (I = subject of both)
- Que + subjunctive (different subject): "Espero que vengas esta noche." — "I hope that you come tonight." (I / you)
- Past tense example: "Esperaba terminar a las cinco." — "I hoped to finish at five." vs. "Esperaba que terminaras a las cinco." — "I hoped that you would finish at five."

Pedir
- Use que + subjunctive to ask someone to do something: "Te pido que me ayudes." — "I ask you to help me." (I / you)
- To request permission or a noun, you can use pedir + noun + para + infinitive: "Pedí permiso para salir." — "I asked for permission to leave." (Note: "Te pido venir" is not natural — prefer "Te pido que vengas" or "Te pido permiso para venir.")
- Past: "Le pedí que viniera temprano." — "I asked him/her to come early." (imperfect subjunctive: viniera)

Necesitar
- Infinitive (same subject): "Necesito terminar esto hoy." — "I need to finish this today." (I must finish it.)
- Que + subjunctive (ask someone else to do it): "Necesito que termines esto hoy." — "I need you to finish this today." (I need you to do it.)
- Note: "Necesito que + subjunctive" is a common way to express that you require someone else to act.

How to form the present subjunctive (brief and practical)

1) Start with the "yo" form of the present indicative: tener → tengo.
2) Drop the final -o: tengo → teng-
3) Add the opposite endings (for present):
- For -ar verbs: e, es, e, emos, éis, en → hablar → hable, hables, hable, hablemos, habléis, hablen.
- For -er/-ir verbs: a, as, a, amos, áis, an → comer → coma, comas..., vivir → viva, vivas...

Irregular/common irregulars you should memorize: tener → tenga, venir → venga, decir → diga, hacer → haga, ser → sea, ir → vaya, saber → sepa, estar → esté, haber → haya.

If the main verb is in the past and you need the subjunctive, use the imperfect subjunctive: (esperaba que) vinieras, (quería que) hicieras.

Common mistakes to avoid

1. Using an infinitive when the subject changes

Wrong: "Necesito que viajar." Correct: "Necesito viajar." (if I travel) or "Necesito que viajes." (if I need you to travel.)

2. Trying to use que + infinitive (no subjunctive) when the subject changes

Wrong: "Quiero que ir." Correct: "Quiero ir." (if I go) or "Quiero que vayas." (if I want you to go.)

3. Using indicative instead of subjunctive after verbs of doubt, desire, request, or emotion

Wrong: "Dudo que viene mañana." Correct: "Dudo que venga mañana." (Subjunctive needed after "dudar".)

4. Confusing impersonal + infinitive vs. impersonal + que + subjunctive

"Es importante estudiar." (general fact) vs. "Es importante que estudies." (it’s important that you study — directed at someone)

Quick cheat sheet

- If the same person does both actions → use the infinitive: "Quiero comer."
- If two different people are involved → use que + subjunctive: "Quiero que comas."
- If the clause begins with a preposition (para, antes de, sin) → use the infinitive.
- If the main clause expresses will/influence/emotion/doubt/necessity and the subordinate clause has a different subject → use que + subjunctive.
- For requests to someone ("pedir"), prefer "pedir que + subjunctive" or "pedir + noun + para + infinitive".

Glossary
- Infinitive: the basic verb form (in Spanish: ends in -ar, -er, -ir). Example: hablar, comer, vivir.
- Subjunctive: a verb mood used for wishes, doubts, demands, emotions, and unreality. It changes form (hable, coma, viva).
- Subject: the person or thing doing the action (yo, tú, él, nosotros...).
- Impersonal expression: a phrase like "Es importante..." that does not name a specific subject.
- Que: here it introduces a subordinate clause (literally corresponds to English "that").

If you're ever unsure, ask: is the actor of the second verb the same person as the actor of the first? If yes, infinitive. If no, use que + subjunctive. The verbs esperar, pedir, and necesitar illustrate this clearly: they take an infinitive when the subject is the same, and they require que + subjunctive when you want someone else to act.