The future perfect continuous tense can be used to show how long an activity or event will have been happening when we look back from the future.
It is formed using the auxiliary verb “will” plus “have been” and “verb-ing”.

Positive: subject + will + have been + verb-ing
Negative: subject + will not + have been + verb-ing
Question: Will + subject + have been + verb-ing?

Common uses:

1. Actions that started in the past and will continue up to a specific point in the future

• By next month, I will have been living in this city for ten years.
• He will not have been studying English for long enough for him to pass the exam next week.
• Will they have been waiting for us for long by the time we arrive?

2. Actions that are expected to be in progress at a particular time in the future

• By 2026, they will have been working at the company for ten years.
• He will not have even been working at the company for a year by the time he gets a promotion.
• Will he have been studying for six hours by the end of the day?

3. Actions that are expected to be completed at a particular time in the future

• By the time I can leave the office, I will have been working for 12 hours!
• When I meet you for lunch, I will have been driving for two hours, so I’ll be tired.
• When she finishes medical school, she will have been studying for six years.