Future perfect tense: formula and examples

An action complete before a future time: "By next month, I will have saved enough for the fee."

With by the time, followed by the present simple: "By the time the guests arrive, we will have cleaned the house."

An amount reached by a future point: "By the end of this year, she will have visited twelve countries."

By means not later than. Until means up to that time, so it doesn't fit here: say "by Friday", not "until Friday".

In British English, will have can also express a confident guess about the past: "You'll have heard the news by now."

The future perfect focuses on a finished result or amount. The future perfect continuous focuses on how long the activity will have lasted. State verbs such as know and own use only the future perfect.

• Wrong: I will have finished the project until Friday.

  Right: I will have finished the project by Friday.

  By means not later than; until means up to that time.

• Wrong: By the time we will arrive, the show will have started.

  Right: By the time we arrive, the show will have started.

  After by the time, use the present simple.

• Wrong: She will have wrote her thesis by May.

  Right: She will have written her thesis by May.

  After will have, use the past participle (written).

• Wrong: By 2028, I will complete my degree.

  Right: By 2028, I will have completed my degree.

  With by + a future time, the future perfect shows completion before that point.

The future perfect is useful in IELTS Writing Task 1 for projections: "By 2050, the population over 65 will have doubled." It shows range without sounding forced. In IELTS Speaking Part 1 or Part 3 it can describe goals ("By next year, I'll have finished my degree"). Check the past participle and the word by each time you use it.

Try each one, then open it to check your answer.

1. 1. Complete this: "By 10 p.m., I ___ (finish) all my homework."

   will have finished

   The action will be complete before a future time.

2. 2. Make this negative: "They will have left by then."

   They won't have left by then.

   Not goes after will.

3. 3. Choose: "Call me after six. I'll have got home (by / until) then."

   by

   By means not later than.

4. 4. Form a question: you / read / the book / by Monday?

   Will you have read the book by Monday?

   Will comes first, then the subject, have and the past participle.

5. 5. Choose: "By December, he will have (lived / been living) here for five years."

   Both are correct.

   With live, the simple and continuous forms both work for duration; the continuous adds emphasis on the activity.

• Future perfect continuous tense
• Future continuous tense
• Future simple tense
• Past perfect tense
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