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


Sir, Please tell me the difference between

1.I promise I’ll have done all the work by next Saturday.
2.I promise I’ll do all the work by next Saturday.

Thank you sir.

Hello deepuips,

In this context there is no difference in meaning. The 'will have' form, sometimes called 'future perfect', tells us that an action will be completed before a certain time. The 'will' form tells us than an action will take place in the future, but not necessarily that it will be completed.

I will eat dinner by three o'clock. - I will start before three but may not finish until after three.

I will have eaten dinner by three o'clock. - My dinner will be finished before three.

In your context 'do the work' already means 'complete the work', so there is no difference in meaning.

I hope that clarifies it for you.

Best wishes,


The LearnEnglish Team

I was studying today's newspaper and this appeared.I am asking it as it is related to what we are discussing

How did the metals get there?
Metals are used in practically every product we use. Even detergents and shampoos have traces of them. Nanoparticles are used to limit body odour in socks, for instance. A lot of this is absorbed by the body and discarded as waste, which enters the sewage system and treatment plants.

So I could have been a millionaire by now?
Since the idea isn’t to sift through individual toilet refuse, no, you would still probably be where you are now. To actually mine the sewage, wastewater is treated through physical, biological and chemical processes, resulting in treated water and biosolids. The biosolids, says US researchers, may be as good as a gold mine.

Sir is the usage ofI could have a been millionaire by now, correct? If yes, the how does it differ from I could be a millionaire by now?

Please explain to me.

Thank you.

Thank you sir.

So sir grammatically Both are right.So what you mean to say is

1.I could be a millionaire by now means I could be a millionaire now.Am I right?Or should I say I could be millionaire now and not use by?I feel the usage of by in present tense seems a bit wrong.

Please help me sir.

Hello deepuips,

It's not unusual to hear both 'could be... by now' and 'could have been... by now'. As I said in my earlier reply, one focuses on something before the time of speaking, whereas the other focuses on a state at the time of speaking. For example:

The dinner might have been cooked by now. [it might be finished any time before the present - let's see if we can eat]

The dinner might be cooked by now. [we'd better check the oven because if we leave it too long it might burn]

Remember that language is highly context-dependent; in order to understand it's use you need to think about it in a concrete situation.

Best wishes,


The LearnEnglish Team

Hello deepuips,

'Could have been' refers to a possible but unreal outcome in the past - becoming a millionaire before the moment of speaking. 'Could be' would refer to a possible situation now - being a millionaire at the moment of speaking. One looks at something which happended before speaking and the other looks at a state at the moment of speaking.

Best wishes,


The LearnEnglish Team


Thank you Peter M sir.I have understood what you have said.On that basis.Please look at this

If I were to apple the same in past then would these two sentence also mean the same

1.I received the book by three o'clock.
2.I had received the book by three o'clock.

Do the above two mean the same sir? If not what is the difference between the two?Please explain to me in simple terms.You, I think, have explained to me so very well, that I feel indebted to you.

Thanking you,

Best wishes,


Hello Deepuips,

The forms here are past simple and past perfect. Past simple ('I received...') is used to describe a completed action in the past. Past perfect ('I had received...') is also used to describe a completed action in the past, but one which has some relation to another, later, action also in the past. This means that the meaning, as such, is not necessarily different, but that we would use the past perfect when there is another action to act as a point of reference.

In other words, if we are simply talking about getting the book then the first sentence is sufficient and correct. If we are also going to talk about another even, after getting the book, to which our getting the book is relevant in some way, then the second sentence would be used. For example:

He arrived at three thirty, but as I had received the book by three o'clock that gave me time to familiarise myself with its contents.

As you can see, context is crucial here. All perfective forms relate an action to another time and/or another action, which is why context is so important.

For more information about the past perfect look here.

For more information about past forms look here.

For more information about perfective forms look here.

I hope that helps to clarify it for you.

Best wishes,


The LearnEnglish Team

Thank you Peter M sir.I sincerely feel you are the best.

Sir as you said about past perfect that simple future that the action may get completed or not, similarly can I infer the same about the simple past?

I mean, when we say

1.I received the book by three o'clock. Can it also mean that I may have received at three o'clock?


2.I had received the book by three o'clock.Can I restrict it to mean that I received it surely before three o'clock?

I mean additionally from the Simple Past and Past Perfect distinction can the above also be one of the differences like we have in the case of Simple Future and Future Perfect?

Thank you nice Peter M sir.

Best wishes.

Hello deepuips,

The distinction is not that one was before three o'clock and one may have been before or at three o'clock; if we say 'by three o'clock then we mean that when that time came we already had it. The distinction is whether we are just describing one event (in which case we use the past simple) or whether we wish to relate one even to a later one in some way (the past perfect). Take a look at my examples in the last answer - they should show this distinction.

Best wishes,


The LearnEnglish Team