Consider these sentences:

They will walk before breakfast.
They will have walked before breakfast.

The first sentence expresses an action that will end before another action occurs in the future. No issues with that.

The second sentence must also express the same information. But somehow it seems to me that it conveys a past action that didn't happen/failed to happen. I know this is incorrect, but I'd like to know more about why this particular tense is throwing me off. Appreciate any help. Thanks.

  • 2
    The second sentence may mean different things depending on contex, because will can be used not only to express future, but also habit or strong probability in a conjecture. Perhaps that's what was nibbling on your brain. Aug 12, 2018 at 15:39

2 Answers 2


...it seems to me that it conveys a past action that didn't happen/failed to happen.

Well, that's wrong. The will establishes that is not the case.

I know this is incorrect...

Well, good.

...but I'd like to know more about why this particular tense is throwing me off.

No one else can really answer why you're making a particular mistake.

My best guess would be that it's a mix of a) no one using the future perfect tense very often and b) your having misunderstood the future tense. It's the verb in the second sentence that specifically expresses an action that will have ended before another action in the future. The verb in the first sentence merely expresses the action will occur sometime in the future.

Of course, like in Chinese, you can get the same point across without conjugating the verb by using an appropriate adverb to lock it in to the appropriate place in time. That is, in fact, why no one really uses the future perfect all that often in English.

Edit: See here for a few cases where some people use it to describe the past. It needs to be in a particular context, though, comparing the other action to something occurring in the present: "Don't call. It's 9 o'clock. She will have already gone to bed by now." Even there, I'd say it's more slipshod than formally correct, but it is an accepted usage.

  • Ah "will" establishes it's not a past action. I see... Thank you :)
    – AgentS
    Aug 12, 2018 at 15:30
  • I think I was getting tripped because I was mixing up Future Perfect with other forms like : 1) She could have passed the exam. 2) He should have started early.
    – AgentS
    Aug 12, 2018 at 15:32
  • @rsadhvika ...or even closer to home, would have..., but all of those are different from the future perfect.
    – lly
    Aug 12, 2018 at 15:35

The modal will has different functions. In the first sentence plain will is used to give information or make a prediction about the future.

The will have construction in the second sentence, out of context, is ambiguous. Again, it can be used to predict the future - specifically about will have happened before another future event. For example:

I will have finished cutting the grass before my wife gets home.

Or in the current case, what they will have done before another future event (breakfast).

But will have can also used to make a supposition about or express the likeliness of a past event. For example, in the following contrived context.

  • Why were they so tired yesterday evening?
  • They will have walked before breakfast.

In other words, you are right that will have walked can refer to a past event. But it is not one that failed to happen. It is the speaker's assessment of what probably happened.

  • In the last example, you'd usually say "they (probably/likely/&c.) walked before breakfast". Even if you were using the future perfect, you'd use its past form "would have". You could use "will've" colloquially but technically incorrectly.
    – lly
    Aug 12, 2018 at 16:16
  • Some people do use it to talk about the past, but only in relation to the present and not to other past events.
    – lly
    Aug 12, 2018 at 16:17
  • 1
    "Will", like other modals, has an epistemic meaning (expressing conclusions or belief) as well as a deontic one (expressing necessity or actuality). That is another reason why it is a nonsense to refer to "will go" etc as a "tense". It is a modal expression (like "can go" and "should go"), one of whose meanings is futurity.
    – Colin Fine
    Aug 12, 2018 at 16:26
  • +1 for being the first to remind us that will + have +PP can be used to express meaning in the past. I think it's quite rare though
    – Mari-Lou A
    Aug 12, 2018 at 16:26
  • @Ily. Certainly the second function of the future perfect, as exemplified above, is rare. But you will hear it in utterances such as: They will have arrived home by now. I'm not sure you can call it technically incorrect.
    – Shoe
    Aug 12, 2018 at 16:42

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