When do we use the future perfect tense in English?
Note: This is also called the future perfect simple tense.
As a general rule, we use the future perfect to talk about actions completed before or by a point in the future.
We use the future perfect for:
1. Actions completed before or by a specific future time
Note: Here we usually use the words before or by. These are similar, but not exactly the same.
Compare:
– before 7 pm = earlier than 7 pm (7 pm is excluded)
– by 7 pm = at or earlier than 7 pm (7 pm is included)
For example:
- I will have finished my work by 7 pm.
(My work will be finished by 7 pm.) - He’ll have left before tomorrow afternoon.
- Sophia will have completed her course by next year.
- They’ll have built the new bridge by November.
- We won’t have had dinner before 6 o’clock.
- Will they have cut the grass by then?
2. Actions completed before another future action
We can use the future perfect to emphasise that one future event happens before another. Here we often use by the time in the other clause.
For example:
- When you get home, he will have cooked dinner.
(Event 1: He cooks dinner. Event 2: You get home.) - We’ll have cleaned the house before our guests arrive.
(Event 1: We clean the house. Event 2: Our guests arrive.) - By the time you hear this message, I will have gone to bed.
(Event 1: I go to bed. Event 2: You hear this message.) - When we get to the airport, the plane won’t have landed yet.
- Will everyone have read the email by the time the meeting starts?
3. Showing durations or amounts of something completed before or by a future point
We often use the future perfect to talk about the length of time (“how long”) or quantity (“how much” or “how many”) of something accumulated up to a point in the future. The point can be a specific time or a future event.
For example:
- In six weeks’ time, the students will have learnt 1,000 new words. (US: learned)
- We will have lived here for six years in July.
- At 2 am, they will have been at the party for eight hours.
- How much money will you have saved by the end of the year?
- How long will she have worked here when she retires?
4. Predictions about something that will already be completed
For example:
- I think I’ll have bought a house by the time I turn 50.
- I’m guessing it will have stopped raining when we get home.
- The movie will have started before we even buy our tickets.
Some time words and phrases that we often use with the future perfect:
- by (e.g. by 7 pm, by June, by next year, by this time next year)
- by the time + present simple
- by then
- by that time
- by the end of
- before (e.g. before 7 pm, before June, before next year, before this time next year)
- before then
- before the end of
- when + present simple
- in (e.g. in six weeks, in six weeks’ time)
- how long
- how much
- how many