The Future Perfect Continuous shows how long an activity will have been in progress at a point in the future. It looks back from that future moment, and it is mostly used with for and by. It is rare in everyday speech, but appears in exams and formal writing.
Form
| Structure | Example |
|---|---|
| subject + will have been + verb-ing | By June I will have been working here for ten years. |
| subject + won't have been + verb-ing | She won't have been waiting long. |
| Will + subject + have been + verb-ing? | How long will you have been studying? |
When to use it
- Duration up to a future point: By 2030 I will have been teaching for 20 years.
- Cause of a future state: She will be exhausted because she will have been working all day.
- Anniversaries: In April they will have been married for 25 years.
Examples
- By December I will have been working here for five years.
- In May we will have been living here for a decade.
- By noon she will have been studying for six hours.
- How long will you have been waiting by then?
- He will be tired – he will have been driving all night.
- They won't have been travelling long when they land.
Common mistakes
- With a completed result: I will have been finishing → I will have finished.
- With state verbs: will have been knowing → will have known.
- Missing “have” or “been”: will been working → will have been working.