Future perfect. Active tense

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.

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?

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?)

before the subject. For example:
Will he have been working?
Will you have finished when I get back?
Will we have made the dinner by 6?