Simple future

What it is

The simple future (futuro simple) says what will happen: Mañana lloverá. Te llamaré. It's common in writing, in predictions and in promises. In everyday conversation, Latin Americans more often use ir a + infinitive: Voy a llamarte.

How to form it

Add the endings to the whole infinitive. They're the same for -ar, -er and -ir verbs:

Every form except nosotros has a written accent.

Irregular stems, with the same endings:

Compounds follow their base verb: mantener → mantendré, proponer → propondré. Hay becomes habrá.

When to use it

• Predictions: Creo que mañana lloverá.
• Promises: Te llamaré sin falta. No diré nada.
• Formal plans and announcements: La reunión será a las diez.
• In conversation, plans you've already made are more often ir a: Este verano voy a viajar a Chile.

• Creo que mañana lloverá.I think it'll rain tomorrow.prediction
• Mañana te llamaré sin falta.I'll call you tomorrow without fail.promise
• Mis papás vendrán en diciembre.My parents will come in December.venir → vendr-

Contrasts and traps

• Not after si (if): Si llueve, nos quedaremos en casa, not Si lloverá.
• Requests use poder: ¿Puedes abrir la ventana?, not ¿Abrirás…?
• Hablaré (I will speak) is not hablare, an old form you'll only meet in legal texts.
• In speech, the future can also be a guess about now: ¿Qué hora será? (I wonder what time it is.) That use comes at B1.

If you also speak Portuguese

The idea matches falarei, farei, direi → hablaré, haré, diré, and Brazilian vou fazer is exactly voy a hacer. But Spanish has more irregular stems: terei → tendré, poderei → podré, saberei → sabré, sairei → saldré, virei → vendré, while trarei is the regular traeré. And se chover is si llueve.