B2 Grammar Tenses

The Future Perfect Tense

The future perfect describes an action that will be completed before a certain point in the future — By next year, I will have finished my degree. It lets you look back from a future moment at something already done.

The future perfect tense describes an action that will be completed before a specific time or event in the future. It allows you to stand at a future point and look back at something that will already have happened: By 8 p.m., the train will have arrived. This is a B2-level structure that adds precision to how you talk about the future.

The key idea is the relationship between two future moments. There is a deadline (a future time or event) and an action that finishes before that deadline. The future perfect connects the two.

Form: Will Have + Past Participle

The future perfect is formed with will have + past participle. This is the same for all subjects (I, you, he, she, it, we, they).

Form Structure Example
Affirmative subject + will have + past participle She will have left by then.
Negative subject + will not (won't) have + past participle They won't have finished by 5.
Question Will + subject + have + past participle? Will you have arrived by noon?
Short answer Yes, … will. / No, … won't. Yes, I will. / No, I won't.

The contraction of will have is often 'll have in speech: I'll have done it. The negative is won't have.

Remember: The past participle is the third form of the verb — finished, left, written, gone, seen. Irregular verbs use their special participle: By June, prices will have risen (not will have rose).

When to Use the Future Perfect

Use the future perfect to say that something will be complete before a future time. It is almost always used with a time expression that marks the deadline.

Time Expressions

Certain time markers signal the future perfect. The most important is by and its relatives, which set the deadline.

Expression Use Example
by + time Deadline = a clock time or date By midnight, I will have finished.
by the time + clause Deadline = another event (present simple) By the time he calls, I will have left.
by then Refers back to a stated future point We move in July; by then we'll have packed.
before + clause/time Action finishes earlier than the deadline I'll have read it before you return.
in + period (looking ahead) Time from now to the deadline In two years, I'll have graduated.

Key rule: After by the time, before and when, use the present simple, not will: By the time you get there (not will get), the shop will have closed. The future perfect goes in the main clause.

Future Perfect Continuous

The future perfect continuous (also called future perfect progressive) emphasises the duration of an activity up to a future point. It is formed with will have been + verb-ing.

Structure: subject + will have been + present participle (-ing)

Future perfect simple Future perfect continuous
Focus on completion / result Focus on duration / ongoing activity
By 5, I will have written ten emails. By 5, I will have been writing emails for hours.
Often used with a number/quantity Often used with for + period

Note that stative verbs (know, be, have, like, believe) are not normally used in the continuous form. Use the simple future perfect with these: By Friday, I will have known her for a year (not will have been knowing).

Future Perfect vs Future Simple

The difference between the two future tenses is about sequence and completion. The future simple (will do) describes an action at or after a future point; the future perfect (will have done) describes an action completed before it.

Future simple Future perfect
When you arrive, I will cook dinner. (I start cooking after you arrive) When you arrive, I will have cooked dinner. (dinner is ready before you arrive)
At 9, the film will start. By 9, the film will have started.

Common Mistakes

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Frequently Asked Questions

What is the future perfect tense?
The future perfect tense describes an action that will be completed before a specific point in the future. It lets you stand at a future moment and look back at something already finished: By next year, I will have graduated. It is formed with will have + past participle and is usually used with a time expression that marks the deadline.
How do I form the future perfect?
Use will have + past participle for all subjects: I will have finished, she will have left, they will have arrived. The negative is won't have + past participle, and questions invert will: Will you have finished by then? In speech, will have is often contracted to 'll have.
What is the difference between future perfect and future simple?
The future simple (will do) describes an action at or after a future point: When you arrive, I will cook dinner (I start cooking after you arrive). The future perfect (will have done) describes an action completed before that point: When you arrive, I will have cooked dinner (it is already ready). The future perfect emphasises completion before a deadline.
What time expressions are used with the future perfect?
The most common is by + a time or date: By midnight, I will have finished. Others include by the time + clause, by then, before, and in + a period (In two years, I'll have graduated). These expressions mark the future deadline by which the action will be complete.
Why can't I use ‘will’ after ‘by the time’?
After time conjunctions such as by the time, when and before, English uses the present simple, not will, even though the meaning is future: By the time you get there, the shop will have closed. The future perfect goes in the main clause, while the time clause stays in the present simple. Saying by the time you will get is a common error.
What is the future perfect continuous?
The future perfect continuous emphasises the duration of an activity up to a future point. It is formed with will have been + verb-ing: By next month, I will have been working here for ten years. While the simple future perfect focuses on completion or result, the continuous focuses on how long the activity will have lasted, often with for + a period.
When should I use the simple rather than the continuous future perfect?
Use the simple future perfect for completed actions and results, especially with a number or quantity: By 5, I will have written ten emails. Use the continuous to stress ongoing duration: By 5, I will have been writing emails for hours. Also use the simple form with stative verbs (know, be, have, like), which are not normally used in the continuous: I will have known her for a year, not will have been knowing.
Can the future perfect express an assumption about now?
Yes. The future perfect can express a confident assumption about something that has probably already happened: Don't call them now — they will have gone to bed. Here you are not talking about the future at all, but making a logical guess about the present or recent past, similar to they must have gone to bed.
How do I make the future perfect negative and into a question?
For the negative, put not after will: They won't have finished by five. For questions, move will to the front: Will you have arrived by noon? Short answers use just will or won't: Yes, I will. / No, I won't. The have + past participle part does not change.
What are some example sentences in the future perfect?
Here are clear examples: By 2030, the city will have built three new bridges. By the time the guests arrive, we will have cleaned the whole house. She won't have read the report before the meeting. Will you have packed everything by tomorrow morning? By June, I will have lived here for five years. Notice each uses a deadline plus will have + past participle.