In short

The futur antérieur is the future’s “past”: it says an action will have been completed before another future moment. Form it with the futur simple of avoir or être plus the past participle - exactly the passé composé, but with the auxiliary in the future.

The rule

The futur antérieur is a compound future. You already know its two ingredients:

• the auxiliary (avoir or être) conjugated in the futur simple (see Lesson 25);
• the past participle of the main verb (the same one you use in the passé composé).

It places one future action before another. The verb in the plain futur simple happens second; the verb in the futur antérieur is finished first.

aurai / serai + past participle

Choose the auxiliary by the same rule as the passé composé:

• Most verbs take avoir: j’aurai fini, tu auras mangé, nous aurons compris.
• The house-of-être / movement verbs and all pronominal verbs take être: je serai parti(e), elle sera arrivée, ils se seront levés.

The only new thing to learn is the future auxiliary itself: aurai, auras, aura, aurons, aurez, auront and serai, seras, sera, serons, serez, seront.

Action completed before a future point

Use the futur antérieur to mark an action already over at a named future time or before another future event:

• Before a clock time / deadline: Dans deux heures, j’aurai terminé le rapport. (In two hours I will have finished the report.)
• Before another future action: Quand tu arriveras, nous aurons déjà mangé. (When you arrive, we will already have eaten.)
• A guess about the past (probability): Il n’est pas là - il aura raté son train. (He must have missed his train.) This is a common conversational use.

The adverb déjà often appears with it to stress “already done”.

With quand, dès que, après que

French is stricter than English here. After the conjunctions quand, lorsque (when), dès que, aussitôt que (as soon as), and après que (after), if the action is finished before the main future action, French uses the futur antérieur - where English happily uses the present perfect or even the simple present.

• Dès que j’aurai fini, je t’appellerai. -> As soon as I have finished, I’ll call you.
• Quand elle sera rentrée, nous dînerons. -> When she gets / has got back, we’ll have dinner.
• Après que tu auras lu le livre, prête-le-moi. -> After you have read the book, lend it to me.

Note the sequence: the futur antérieur clause is the earlier event; the futur simple (or imperative) clause is the later one.

Agreement of the past participle

The same agreement rules as the passé composé apply:

• With être: the participle agrees with the subject - elle sera partie, ils seront venus.
• With avoir: no agreement with the subject, but agreement with a direct object placed before the verb - les lettres que j’aurai écrites.

Forms & patterns

Auxiliaries in the futur simple:

Full paradigm - finir (avoir) and partir (être):

Pronominal verb - se lever:

Examples

Common mistakes

• Quand je finis, je t’appellerai -> Quand j’aurai fini, je t’appellerai - the earlier of two future actions takes the futur antérieur; don’t fall back on the present as English does.
• Si j’aurai fini à temps, je viendrai -> Si j’ai fini à temps, je viendrai - si (if) never takes a future tense, not even the futur antérieur; only time words like quand and dès que do.
• elle sera parti -> elle sera partie - with être, the participle agrees with the subject.
• j’aurai allé -> je serai allé(e) - aller is a movement verb; it takes être, not avoir.
• je me aurai levé -> je me serai levé - pronominal verbs always use être.
• nous serons mangé -> nous aurons mangé - manger takes avoir; don’t mix the auxiliaries up.

Tips

• Build it in two steps: take the passé composé, then swap the auxiliary into the futur simple. J’ai fini -> j’aurai fini.
• Ask “will this be done before something else in the future?” If yes, use the futur antérieur.
• The auxiliary choice is identical to the passé composé - if you know one, you know the other.
• Watch the trigger words quand, lorsque, dès que, aussitôt que, après que: they often force the futur antérieur where English keeps a present tense.
• déjà is your friend - it naturally pairs with “will already have done”.
• In speech, a futur antérieur with no future time reference often means a guess about the past: Il aura oublié = “He’s probably forgotten.”