Do you know when to use the future continuous (e.g. I'll be studying) and future perfect (e.g. I'll have studied)?

The future continuous (will be + ‘ing’ form) and the future perfect (will have + past participle) tenses are used to talk about events in the future.

Future continuous

  • Don’t ring at 8 o’clock. I’ll be watching Who Wants to be a Millionaire.
  • This time tomorrow we’ll be sitting on the beach. I can’t wait!

We use the future continuous to talk about something that will be in progress at or around a time in the future.

  • Don’t phone grandma now, she’ll be having dinner.
  • The kids are very quiet. They’ll be doing something wrong, I know it!

These sentences are not about the future but we can use the future continuous to talk about what we assume is happening at the moment.

Future Perfect

  • Do you think you will have finished it by next Thursday?
  • In 5 years time I’ll have finished university and I’ll be able to earn some money at last.

We use the future perfect to say that something will be finished by a particular time in the future.

We often use the future perfect with ‘by’ or ‘in

  • I think astronauts will have landed on Mars by the year 2020.
  • I’ll have finished in an hour and then you can use the computer.

By’ means ‘not later than a particular time’ and ‘in’ means 'within a period of time’. We don’t know exactly when something will finish.

  • I promise I’ll have done all the work by next Saturday.

We don’t know exactly when he will finish the work – maybe Thursday, maybe Friday – but definitely before Saturday. 


Language level

Upper intermediate: B2


In one of the previous messages, two sentences were discussed:
1) I think astronauts will land on Mars by the year 2020.
2) I think astronauts will have landed on Mars by the year 2020.
Kirk replied that both alternatives are possible.
If you don't mind, I'd like to add a question of my own.
1) Does it mean that we can always use both Future Simple and Future Perfect interchangeably in similar sentences with 'by'? For example:
- By the year 2040 the world's population will reach/will have reached 9 billion.
- We will get back/will have got back to the hotel by seven.
- In ten years' time I'll get married and have three kids / I'll have got married and had three kids.

Perhaps the degree of certainty might be different? What do you think?
Thank you very much for your answer!

Hello EvgenyAndreev,
Both options are possible and there is no difference in meaning in these examples. The by-phrase already contains a sense of 'complete before' so it makes no difference if 'will' or 'will have' is used.
The LearnEnglish Team

Hi sir,
Considering the two phrase, "In five years time","in 10 year's time", which one is correct?
I mean the word "years" without apostrophe 's' is correct or the word with apostrophe 's ,is correct.
Thanks ,

Hello again David

The correct spelling is 'in five years' time' or 'in ten years' time'. This apostrophe indicates possession (of a sort) and it comes after the letter 's' because 'years' is plural.

All the best


The LearnEnglish Team

I promise I’ll have done all the work by next Saturday.
In this sentence, is it possible that the person finish the work on Saturday?

Hello Harry New,

Generally, when we use will have with a by construction we consider it to refer to a time before the identified moment. However, in normal communicative use the context will determine this. It is possible that the speaker means 'before next Saturday', 'before I see you next Saturday', 'before I come to work next Saturday' etc.



The LearnEnglish Team

Excuse me, this sentence has come in an English test and I'd like to know the right answer: - Friday has the ...................... number of cars on roads.
(least- fewest- less- fewer)
Some teachers say it's the least, but others say the fewest and I'm a little confused.

Hello muhammadShaker

'the fewest cars' and 'the lowest number of cars' (or 'the smallest number') are the best forms here; 'the least number' is also used sometimes but is not really correct. 'fewest' can only be used with a plural count noun (such as 'cars', but not 'number'). 'least' is used in many ways, but it used with uncount nouns -- 'number' is not an uncount noun here.

All the best


The LearnEnglish Team


I saw a sentence on the Internet, which reads: "I will be leaving for the UK at 7:00 in the evening." As I think "leave", similar to "arrive", can only occur at a particular point of time, I am quite confused as to why future continuous is used in this sentence.


Hi patph0510,

The continuous aspect can be used to convey a variety of meanings and these are often not clear without knowing the context. In this case, I expect the person who said this was thinking of their departure for the UK and was imagining it as something that would take some time. If they were flying, for example, they'd have to get to the airport, check in, go to their gate, board the plane, get settled, etc. At some point during that process, the clock would strike 7.00.

We often use the future continuous to speak about planned or arranged events in this way.

All the best,
The LearnEnglish Team