Use:
Use the future perfect to talk about an event that will be finished and complete before a specified time in the future.
This time next week, I’ll will have finished this project.
Phrases often seen with this use of the future continuous include:
By ..., This time next week..., In __ years’ time...; when + present simple; by the time + present simple.
When you arrive, I’ll have prepared the dinner.
By the time I get home, my mum will probably have tidied the house.
The future perfect is also use to make predictions about future events that will be complete before a specified future time.
Do you think Mel will have eaten all the chocolate cake?
No, she won’t have done that!
Form:
Make the future continuous this way:
Positive and Negative
I
you
he / she it
we
they
will have
won’t have
past participle
Questions
Will
Won’t
I
you
he / she it
we
they
have
past participle?
Be going to is rarely used to make the future perfect tense.
Tom’s going to have finished his lecture by the time we get there.