The future perfect is a verb form or construction used to describe an event that is expected or planned to happen before a time of reference in the future, such as will have finished in the English sentence "I will have finished by tomorrow." It is a grammatical combination of the future tense, or other marking of future time, and the perfect, a grammatical aspect that views an event as prior and completed.
In English, the future perfect construction consists of the auxiliary verb will (or shall; see shall and will) to mark the future, the auxiliary verb have to mark the perfect, and the past participle of the main verb (the second component of the English perfect construction). For example:
- She will have fallen asleep by the time we get home.
- I shall have gone by then.
- Will you have finished when I get back?
The first auxiliary may be contracted to 'll: see English auxiliaries and contractions. The negative form is made with will not or shall not; these have their own contractions won't and shan't. Some examples:
- I'll have made the dinner by 6.
- He won't have done (or will not have done) it by this evening.
- Won't you have finished by Thursday? (or Will you not have finished by Thursday?)
Most commonly the future perfect is used with a time marker that indicates by when (i.e. prior to what point in time) the event is to occur, as in the previous examples. However it is also possible for it to be accompanied by a marker of the retrospective time of occurrence, as in "I will have done it on the previous Tuesday". This is in contrast to the present perfect, which is not normally used with a marker of past time: one would not say *"I have done it last Tuesday", since the inclusion of the past time marker last Tuesday would entail the use of the simple past rather than the present perfect.
The English future perfect places the action relative only to the absolute future reference point, without specifying the location in time relative to the present. In most cases the action will be in the future relative to the present, but this is not necessarily the case: for example, "If it rains tomorrow, we will have worked in vain yesterday."
The future perfect construction with will (like other constructions with that auxiliary) is sometimes used to refer to a confidently assumed present situation rather than a future situation, as in "He will have woken up by now."
The time of perspective of the English future perfect can be shifted from the present to the past by replacing will with its past tense form would, thus effectively creating a "past of the future of the past" construction in which the indicated event or situation occurs before a time that occurs after the past time of perspective: In 1982, I knew that by 1986 I would have already gone to prison. This construction is identical to the English conditional perfect construction.
In Spanish, the future perfect is formed as such:
The future of haber is formed by the future stem haber + the endings -é, -ás, -á, -emos, -éis, -án. The past participle of a verb is formed by adding the endings -ado and -ido to ar and er/ir verbs, respectively. However, there are a few irregular participles, some of the more common ones listed here:
Be aware that verbs within verbs also have the same participle, for example, predecir ("to predict') would be predicho; suponer ("to suppose") would be supuesto. Also, satisfacer ("to satisfy") is close to hacer ("to do") in that the past participle is satisfecho.
To make the tense negative, one simply adds no before the form of haber: yo no habré hablado. For use with reflexive verbs, one puts the reflexive pronoun before the form of haber: from bañarse ("to take a bath"), yo me habré bañado; negative: yo no me habré bañado.
In Portuguese, the future perfect is formed similarly to Spanish as: "subject + future of ter or haver + past participle ". The use of the auxiliary verb haver to form the future perfect is, however, very rare in modern Portuguese.
- eu terei falado ("I will have spoken")
The future of ter is formed by the future stem ter + the endings -ei, -ás, -á, -emos, -eis, -ão (the 2nd person plural form tereis is, however, archaic in both European and Brazilian Portuguese). The past participle of a verb is formed in turn by adding the endings -ado and -ido to the stems of -ar and -er/-ir verbs, respectively. However, there are a few irregular participles, the most common of which are listed below:
- abrir: aberto
- cobrir: coberto
- dizer: dito
- escrever: escrito
- fazer: feito
- ganhar: ganho
- gastar: gasto
- pagar: pago
- pôr: posto
- ver: visto
- vir: vindo
Several verbs that are derived from the irregular verbs above form their past participle in a similar fashion, for example, the past participle of predizer ("to predict') is predito; for supor ("to suppose"), it would be suposto, and satisfazer ("to satisfy"), which is derived from fazer ("to do"), has the past participle satisfeito.
To make the sentence negative, one simply adds não before the conjugated form of ter: eu não terei falado. When using the future perfect with oblique pronouns, European Portuguese and formal written Brazilian Portuguese use mesoclisis of the pronoun in the affirmative form and place the pronoun before the auxiliary verb in the negative form.
- Eu tê-lo-ei visto ("I will have seen him")
- Eu não o terei visto ("I will not have seen him")
- Eles ter-me-ão visto ( "They will have seen me")
- Eles não me terão visto ("They will not have seen me")
Informal Brazilian Portuguese on the hand usually places stressed pronouns such as me, te, se, nos and lhe/lhes between the conjugated form of ter and the past participle, for example: eles terão me visto; in the negative form, both eles não terão me visto and eles não me terão visto are possible, but the latter is more formal and, hence, preferred in the written language. Unstressed pronouns like o and a are normally placed before the conjugated form of ter, for example: eu o terei visto; eu não o terei visto.
The French future perfect, called futur antérieur, is formed similarly to Spanish:
avoir or être
Verbs that use être in the past ("House of Être" verbs, reflexive verbs) also use être in forming the present perfect. For example, je serai venu(e) uses the future of être because of the action verb, venir (to come), which uses être in the past.
To form the future form of the auxiliary verbs, one uses the future stem and adds the endings -ai, -as, -a, -ons, -ez, -ont. Both avoir and être have irregular future stems; while, with the exception of -re verbs, most verbs use the infinitive as the future stem (e.g. je parler-ai, I will speak), the future stem of avoir "is" aur-, and that of être is ser-.
To form the past participle in French, one usually adds -é, -i, and -u to the roots of -er, -ir, and -re verbs, respectively. However, there are many exceptions to this rule, including these commonly used ones (and all of their related verbs):
- faire: fait
- mettre: mis
- ouvrir: ouvert
- prendre: pris
- venir: venu
Verbs related to mettre ("to put"): promettre ("to promise"); to ouvrir: offrir ("to offer"), souffrir ("to suffer"); to prendre ("to take"): apprendre ("to learn"), comprendre ("to understand"); to venir ("to come"): revenir ("to come again"), devenir ("to become").
When using être as the auxiliary verb, one must make sure that the past participle agrees with the subject: je serai venu ("I [masc.] will have come"), je serai venue ("I [fem.] will have come"); nous serons venus ("We [masc. or mixed] will have come"), nous serons venues ('We [fem.] will have come"). Verbs using avoir do not need agreement.
To make this form negative, one simply adds ne (n' if before vowel) before the auxiliary verb and pas after it: je n'aurai pas parlé; je ne serai pas venu. For reflexive verbs, one puts the reflexive pronoun before the auxiliary verb: from se baigner ("to take a bath"), je me serai baigné; negative: je ne me serai pas baigné.
The future perfect in German (called Futur II or vollendete Zukunft) is formed in a similar fashion to English by taking the simple future of the past infinitive, i.e. one uses the simple future of the auxiliary sein (= ich werde sein, du wirst sein etc.) or haben (= ich werde haben, du wirst haben etc.) and the verb you conjugate in the past participle (ich werde gemacht haben, du wirst gemacht haben etc.). For example:
- Ich werde etwas geschrieben haben.
- "I will have written something."
- Morgen um diese Uhrzeit werden wir bereits die Mathe-Prüfung gehabt haben.
- "Tomorrow at the same time we already will have had the math exam."
- Es wird ihm gelungen sein
- "He will have succeeded."
- Wir werden angekommen sein
- "We will have arrived."
The Dutch future perfect tense is very similar to the German future perfect tense. It is formed by using the verb zullen ("shall"), then placing the past participle and hebben ("to have") or zijn ("to be") after it. Example:
- Ik zal iets geschreven hebben.
- "I shall something written have."
- "I will have written something."
The Afrikaans future perfect tense is very similar to the Dutch future perfect tense. It is formed by using the verb sal ("shall") followed by the past participle and het (conjugated form of the verb hê). Example:
- Ek sal iets geskryf (*) het.
- "I shall something written have."
- "I will have written something."
(*) Note that, unlike in Dutch, almost all past participles in Afrikaans are regular (with a few exceptions like gehad and gedag). The Dutch strong participles are, however, sometimes preserved in Afrikaans when the participles are used as adjectives.
- Dutch: Ik zal een brief geschreven hebben
- Afrikaans: Ek sal 'n brief geskryf het
- English: "I will have written a letter"
- Dutch: een geschreven brief
- Afrikaans: 'n geskrewe brief
- English: "a written letter"
- "I will have finished by then"
- Θα έχω τελειώσει ... ("have" + infinitive)
- Tha écho teliósi ...
- "I will be hired by then"
- θα είμαι προσληφθείς ... ("be" + participle)
- Tha íme proslifthís ...
In Latin conjugation the future perfect is found by using the perfect stem + a declined future being verb (ero). An exception is that the active indicative 3rd person plural is formed from the perfect stem + erint, instead of + erunt. E.g., amaverint, not amaverunt.
The future perfect active is formed thus:
|perfect stem||+||future perfect
|We shall have spoken|
The future perfect passive is formed thus:
|perfect passive participle||+||future of
|have been loved||I will|
The future perfect is used to say that something will happen in the future, but before the time of the main sentence. It is called futuro anteriore and is formed by the auxiliary verbs "to be" (essere) and "to have" (avere) in the future simple tense -transitive or intransitive verb-, adding the past participle. For example:
Io avrò mangiato ("I will have eaten")
Io sarò andato/a ("I will have gone")
It is used for the Italian deduction in the past as the same meaning of "must";[clarification needed] also for the English expression "By the time/When I have done this, you will have done that" Italian uses the double future : "By the time/When I avrò fatto this, you avrai fatto that".
It is usually restricted only to conditional clauses. It is formed from a conjugated form of auxiliary verb biti ("to be") in the imperfective aspect plus past participle, which can be in any aspect and is conjugated for gender and number. Since Serbo-Croatian has a developed aspect system this tense is considered redundant.
Kad budem pojeo... ("When I will have eaten...")
Nakon što budeš gotov... ("After you will have been done...")
See also 
- Comrie, Bernard. 1985. Tense. Cambridge: Cambridge Univ. Press, p. 73.
- Comly, John. 1811. A new spelling book, adapted to the different classes of pupils. Philadelphia: Kimber and Conrad.
- Murray, Lindley. 1827. An abridgment of L. Murray's English grammar. Boston: James Loring.