The future perfect tense is used to describe an action that will have been completed at a certain point of time in the future. Consider this situation. You are working on a project and you will finish it in two months. Then at the end of two months, you will have completed that project. Note the form of the verb in used in this tense: will / shall + have + past participle form of the verb.
The future perfect tense is commonly used with a future time expression like by next week, by the end of this year etc.
- The train will have left by the time you reach the station. (Here the phrase by the time you reach identifies a certain point of time in the future.)
- I will have moved into my new office by the end of this month.
- I will have eaten every chocolate in that box before my mom returns from work.
- Susan will have finished her studies before she gets married.
Negative forms are made by putting not after will / shall.
- I will not have learned my lessons before dad arrives.
- We will not have repaired the roof before monsoon sets in.
The question forms are made by putting will / shall before the subject.
- Will you have gone to bed before I arrive?
- Will they have returned the money before the end of this week?
An overview of the future tenses
The future perfect tense is one of the four future tenses. Here is an overview of the other three future tense forms.
Simple future
Form: will / shall + infinitive.
- She will come.
- I shall help you.
Future continuous
Form: will / shall + be + -ing form of the verb.
- She will be working on that report now.
- They will be having dinner.
Future perfect continuous tense
Form: will / shall + have + been + -ing form of the verb
- She will have been writing an essay.
Note that this tense form is very rarely used.