Futur antérieur
Summary
The futur antérieur expresses an action that will be completed before another future moment ('will have done'), formed with the future simple of avoir or être plus the past participle.
Explanation
The futur antérieur is a compound tense formed with the futur simple of the auxiliary avoir or être + the past participle: j'aurai fini, tu auras fini, il aura fini, nous aurons fini, vous aurez fini, ils auront fini; and with être, je serai parti(e), tu seras parti(e), il sera parti, nous serons parti(e)s, ils seront partis. The auxiliary carries the future endings (-ai, -as, -a, -ons, -ez, -ont), and only the participle changes from verb to verb.
Choosing the auxiliary and agreeing the participle work exactly as in the passé composé. The usual verbs of movement and change of state take être (aller, venir, partir, arriver, naître, mourir…), as do all pronominal verbs (je me serai levé), and their participle agrees with the subject (elle sera partie, nous serons arrivés). With avoir there is no agreement with the subject, but the participle agrees with a preceding direct object.
Its main use is to mark an action that will already be finished before another future moment ('will have done'). It is extremely common after quand, lorsque, dès que, une fois que and après que: the action that finishes first goes in the futur antérieur and the later one in the futur simple — Quand j'aurai fini, je t'appellerai. It also expresses a supposition or probability about the recent past: Il aura oublié ('He must have forgotten'), Elle aura raté son train ('She has probably missed her train').
The chief pitfall is putting both verbs in the same future tense after quand: French uses the futur antérieur for the prior action where English uses the present perfect ('When I have finished…' = Quand j'aurai fini…, not *Quand je finirai…). Be careful to order the two futures correctly — the earlier-completed action is the antérieur — and do not forget participle agreement with être (elle sera partie, not parti).
Rule of thumb: future of the auxiliary + past participle = 'will have done'. With quand, dès que or une fois que, put the action that finishes first in the futur antérieur and the following one in the futur simple; choose the auxiliary and agree the participle exactly as in the passé composé.
Examples
Quand j'aurai fini mes devoirs, je sortirai. — When I have finished my homework, I will go out. (aurai fini (futur antérieur) is completed before sortirai (futur simple).)
Dans deux ans, ils auront terminé leurs études. — In two years, they will have finished their studies. (A point in the future (dans deux ans) by which the action will be complete.)
Dès qu'elle sera arrivée, nous mangerons. — As soon as she has arrived, we will eat. (être verb: arrivée agrees with the feminine subject elle.)
Il aura oublié, c'est sûr. — He must have forgotten, that's for sure. (Here the futur antérieur expresses a supposition about the past, not a future action.)
Une fois que tu auras lu ce livre, tu comprendras. — Once you have read this book, you will understand. (une fois que + futur antérieur for the prior action, futur simple for the result.)
Common mistakes
Quand tu arriveras, je finirai déjà mon travail.
Quand tu arriveras, j'aurai déjà fini mon travail.
After quand when one future action is completed before another, French requires the futur antérieur (aurai fini) for the prior action, not the futur simple. Finirai simply states a future action without marking that it precedes arriveras; aurai fini expresses that the work will already be done by the time you arrive.
Prerequisites
Related rules
future-tensecompound-tenseanteriority