C1-C2 grammar reference
Future Perfect Progressive
The future perfect progressive looks back from a future point and measures how long an activity will have been continuing by then. Its main focus is accumulated duration.
Form at a glance
Form: subject + will have been + verb-ing
When to use it
- Duration up to a future point:
By July, I will have been working here for five years.
- Explaining a future condition:
They will be tired because they will have been travelling all night.
- A repeated activity measured at a future point:
Next month, she will have been commuting weekly for a year.
Sentence patterns
| Form | Pattern | Example |
|---|---|---|
| Affirmative | S + will have been + V-ing | He will have been studying for hours. |
| Negative | S + will not have been + V-ing | I won't have been waiting long. |
| Question | Will + S + have been + V-ing? | Will they have been living there long? |
| Duration | by + point + for + period | By noon, we will have been walking for four hours. |
Compare the meaning
Future perfect progressive
Duration/activity: She will have been teaching for twenty years.
Future perfect simple
Completion/quantity: She will have taught twenty courses.
Common mistakes
- Keep the complete auxiliary chain: will have been + -ing.
- Use for with a duration and since with a starting point.
- Avoid this form with most stative verbs; use
will have known
, notwill have been knowing.
Nuance and natural usage
- This form is relatively uncommon because speakers often choose a simpler tense when duration is not central.
- The activity may continue after the future reference point; the tense only measures it up to that point.