See it in action
Level B1Read or listen first. Don’t worry about the rules yet — just notice the verbs in bold.
Marathon day
Eva: The marathon starts at nine. When do you think you’ll finish?
Dan: Around two. By then, I’ll have been running for five hours — and I’ll have been training for a whole year!
Eva: How long will your family have been waiting at the finish?
Dan: Two hours, maybe. They’ll have been standing in the cold since noon.
Eva: Poor things! I’ll bring them a hot drink.
Quick check
Look at the verbs in bold. Which form do they all share?
The future perfect continuous is will have been + -ing: will have been running, will have been waiting.
Quick check
When does Dan’s family start waiting at the finish?
They start at noon. By two, they’ll have been waiting for about two hours: the tense measures time up to a future moment.
When to use it
Level B1–B21. How long an activity will have lasted by a future moment
When she retires, she’ll have been teaching for forty years.
2. Confident guesses about an activity
You can’t see it, but you’re sure an activity has been going on, because of what you know. A result often follows with so.
Don’t call him now — he’ll have been driving all night.I’m sure he has been.
She’ll have been revising all day, so she’ll want a break.
3. The cause of a future situation
Explain a future situation (tired, wet, hungry…) with the activity that will cause it: because + will have been + -ing.
They’ll be exhausted because they’ll have been travelling all day.
He’ll be soaking wet when he gets home because he’ll have been walking in the rain.
Quick check
“When she retires, she’ll have been teaching for forty years.” Is she a teacher now?
The activity started in the past and continues up to a future moment (when she retires).
Form: will have been + -ing
Level A2–B1The form is the same for every subject.
| All subjects | |
|---|---|
| Positive | she will have been working (she’ll have been) |
| Negative | she won’t have been working |
| Question | Will she have been working…? |
| Short answer | Yes, she will. / No, she won’t. |
By June, I’ll have been learning Japanese for two years.
Will you have been waiting long by the time I get there?
Quick check
Which sentence is correct?
Every part is fixed: will + have + been + -ing.
for, by the time and How long…?
Level A2–B1for + the length of time · by / by the time / when + the future moment.
By six o’clock, I’ll have been cooking for three hours.
By the time the guests arrive, she’ll have been cooking since three o’clock.since + the moment it started.
How long will you have been living here by next summer?How long + will + subject + have been + -ing?
After by the time and when, use the present simple, not will:
Wrong: By the time the guests will arrive, …By the time the guests arrive, she’ll have been cooking for two hours.
Quick check
By Friday, we’ll have been working on this project ___ six months.
for + a length of time (six months). since needs a starting point (since March).
Quick check
By the time you ___, I’ll have been waiting for an hour.
After by the time and when, use the present simple for the future.
will have been doing or will have done?
Level B1–B2Use the continuous for the activity and how long it lasts; use the simple for a completed amount or result.
By Friday, I’ll have been writing this report for a week.
By Friday, I’ll have written ten pages.A completed amount: simple.
Tom will still be cooking at six: he’ll have been cooking for two hours by then.Still going on at that moment: continuous.
State verbs (know, have, own, believe, belong…) stay in the simple:
Wrong: They will have been knowing each other for ten years.They will have known each other for ten years by the time they get married.
With live, work, teach and study + for, both forms are fine: She’ll have lived / have been living here for ten years.
Quick check
By Friday, I’ll have ___ ten pages.
A completed amount (ten pages) takes the simple form: I’ll have written.
will have been doing or will be doing?
Level B2At six o’clock, I’ll be cooking.In progress at that moment.
By six o’clock, I’ll have been cooking for three hours.How long up to that moment.
Wrong: By six o’clock, I’ll be cooking for three hours.By six o’clock, I’ll have been cooking for three hours.
Quick check
By the end of the day, she ___ for ten hours.
for ten hours + by = how long up to a future moment: the future perfect continuous.
Advanced uses
Level B2–C2Once the basics feel easy, use this tense for assumptions and for milestones.
Show the advanced uses
Assumptions and causes
At higher levels the guesses and causes get longer, but the pattern is the same: will have been + -ing for the activity, then the result (so…) or the situation (…because).
She’ll have been revising all weekend, so she’ll need some sleep.A guess, then the result.
He’ll have no voice left when he gets home because he’ll have been shouting at the match.The situation, then its cause.
Quick check
“He’ll have been driving all night, so he’ll be exhausted.” How sure is the speaker that he drove all night?
will have been + -ing here is a confident assumption about an activity, based on what the speaker knows.
Milestones and anniversaries
Say how long something will have lasted when a special moment comes — an anniversary, a retirement, a birthday: will have been + -ing + for + the total time, then by…, next… or when / by the time + present simple.
Next spring, my parents will have been living in Canada for twenty years.
By 2030, she will have been running the company for a quarter of a century.
He’ll have been playing in the orchestra for thirty years when he retires.when + present simple.
Wrong: By 2030, she has been running the company for 25 years.By 2030, she will have been running the company for 25 years.The milestone is in the future: will have been.
Quick check
“By 2030, she will have been running the company for a quarter of a century.” When did she start running it?
A quarter of a century is 25 years, counted back from 2030: she started in 2005.
Common mistakes
Level AllWrong: She will has been working.She will have been working.After will, always the base form.
Wrong: They will have being waiting.They will have been waiting.
Wrong: I will have been worked here for a year.I will have been working here for a year.
Wrong: By the time you will get here, …By the time you get here, …
Wrong: She won’t has been working long.She won’t have been working long.
Wrong: By June, I’ll have been having this car for ten years.By June, I’ll have had this car for ten years.State verbs (have, know, own): no -ing.
Wrong: Yes, I’ll.Yes, I will.Don’t contract positive short answers.
Wrong: Will she have been waiting long? — Yes, she does.Will she have been waiting long? — Yes, she will.The question starts with will, so the answer uses will / won’t.
Remember
- will have been + -ing says how long an activity will have lasted up to a future moment.
- for + the length of time; by / by the time / when + the future moment: By six, I’ll have been cooking for three hours.
- After by the time and when, use the present simple: By the time you get here…
- Completed amounts and state verbs take the future perfect simple: I’ll have written ten pages, they’ll have known.
- In progress at a moment, with no “how long” → future continuous: At six, I’ll be cooking.
Practise the future perfect continuous
Pick your level. Gap-fills, How long…? questions, time clauses, simple vs continuous, “find the mistake” and more — new exercises every time.
- A1BeginnerFirst steps: will have been + -ing up to a future moment.Start
- A2ElementaryNegatives, questions, short answers and How long…?Start
- B1Intermediatefor + by / by the time, and will have done vs. been doing.Start
- B2Upper intermediateTime clauses, assumptions and will be doing vs. been doing.Start
- C1AdvancedMilestones, causes and subtle simple vs. continuous choices.Start
- C2ProficientAnniversaries, formal milestones and tricky state verbs.Start