"Future Perfect" используется, когда речь идёт о действии, которое должно закончиться до определённого момента в будущем :
Tom is a football fan and there is a football match on television this evening.
The match begins at 7.30 and ends at 9.15.
Ann wants to come and see Tom this evening and wants to know what time to come.
Ann: Is it all right if I come about 8.30?
Tom: No, don't come then. I'm going to watch the match on TV.
Ann: O.k. What about 9.30?
Tom: Yes, that will be fine. The match will have finished by then.