What does will have mean?

Will have plus a past participle means the action is complete before a point you are looking at. That point can still be ahead (By dusk we will have pressed the last apples) or it can be now (They'll have stacked the crates by now). The first is a completed future; the second is a deduction from present evidence.

What is the difference between will have and would have?

Will have aims at a real later deadline or infers a real present. Would have aims at a past that did not happen, usually the result of a third conditional: We would have finished sooner if the mill hadn't jammed. Swap them and a plan becomes a regret. They share have plus a participle and nothing else of their time reference.

Is will have the same as the future perfect tense?

It is the same string. The future-perfect page treats the tense as a system, with duration (In October I will have kept bees for twenty years) and by-phrases. This page sets that string beside would have, so you can see the pair: completed future versus imagined past. Use either page depending on which neighbour you need.

Can I say if I would have instead of if I had?

Not in standard English. The if-clause of a third conditional takes the past perfect: If I had checked the belts, the mill would have run. Would have stays in the result. If I would have checked is widely heard in speech and is still marked as an error in careful writing.

How is would have different from must have or might have?

Must have is a confident deduction from evidence (The floor is wet; they must have washed it). Might have is an open past possibility. Would have is either an unreal past result or a reconstruction you treat as the expected past (She would have taken the upper path). All three take have plus a participle; the modal is what changes the job.

English grammar · Intermediate

Will Have and Would Have: Completion and Past Speculation

Written by Eleanor Whitfield, Lead English Curriculum Editor · Reviewed September 2026

Will have plus a past participle looks forward to a point and treats an action as already complete there (By dusk we will have pressed the last of the apples) or makes a confident deduction about now (They'll have stacked the crates by now). Would have plus a past participle looks back at a past that did not happen: the result half of a third conditional, or speculation about a missed chance (We would have finished sooner if the mill hadn't jammed). The two strings share a shape and split on time and reality.

By dusk we will have pressed the last of the apples; we would have finished sooner if the mill hadn't jammed.

will have for a completed future; would have for an imagined past

What it is

Will have and would have are not tenses in the school-book sense so much as two modal strings built on have plus a past participle. Will have stands at a future deadline (or at now, with the speaker looking at evidence) and says the action is already done from that vantage point. Would have stands in an unreal past and says what the result would have been. A dedicated future-perfect page covers the tense as a system with by-phrases and duration; a past-modals page covers must have, should have, and could have. This page keeps the pair: will have versus would have.

By the time the cooper arrives, we will have racked the cider. (deadline still ahead, work complete) We would have racked it yesterday if the press hadn't cracked. (yesterday is closed, and we did not rack it)

How to spot it

Look for will have or would have immediately followed by a past participle, with no to: will have pressed, would have jammed. A by-phrase or by now usually signals will have. An if-clause with the past perfect, or a sentence about a missed chance, usually signals would have.

By Friday they will have bottled the first vat. (completion before a future deadline)
They'll have stacked the crates by now. (confident deduction about the present)
We would have lost the whole pressing if the mill hadn't jammed when it did. (imagined past result)
She would have been in the orchard; her boots are still muddy. (speculation about a past location)

Would have is also the backshift of will have: I'll have finished becomes she said she would have finished. The form is identical to the conditional, so the reporting verb tells you which job it is doing.

Will Have and Would Have Quick Reference

Will have versus would have

String	Job	Example
will have + past participle	complete before a future point	By dusk we will have pressed the last apples.
will have + past participle	confident deduction about now	They'll have stacked the crates by now.
would have + past participle	third-conditional result	We would have finished if the mill hadn't jammed.
would have + past participle	past speculation without if	She would have taken the upper orchard path.
won't have + past participle	not complete by the deadline, or a negative deduction	We won't have bottled it by Friday.
wouldn't have + past participle	negative imagined past	I wouldn't have left the press running.

Common Will Have and Would Have Examples in English

Four jobs, two strings: will have looks forward or infers now; would have looks back at what did not happen:

Completed Future

By dusk we will have pressed the last of the apples.: the pressing is complete before dusk
The cooper will have hooped the barrels before the lorry comes.: deadline named with before
In October I will have kept bees on this orchard for twenty years.: duration measured up to a future point
Will you have racked the cider by the time the inspector calls?: asking whether completion beats the deadline

This is the future-perfect use in modal clothing. A by-phrase or by the time almost always sits with it; without a deadline the sentence often sounds unfinished.

Deductions about Now

They'll have stacked the crates by now.: evidence plus time: a confident assumption
Don't ring the cider house; they'll have locked up.: present result of a past action, inferred
She'll have taken the upper path; her boots are muddy.: present evidence for a recent action
The wasps will have found the fallen fruit already.: already marks the deduction as overdue

Must have is a close cousin for deduction (They must have stacked the crates). Will have sounds like a prediction that has already come true, slightly less like a detective's conclusion.

Third Conditional Results

We would have finished sooner if the mill hadn't jammed.: unreal past result plus unreal past condition
If she had checked the belts, the mill would have run all morning.: if-clause past perfect, result would have
I would have saved the last russets for you, but the wasps got there first.: but-clause standing in for if
Without that spare belt, we would have lost the whole pressing.: without packing the condition into a phrase

Would have belongs in the result clause. The if-clause takes the past perfect (if the mill hadn't jammed), never would have. If I would have jammed is the error this pattern is built to stop.

Past Speculation

She would have been in the upper orchard around noon.: a guess about a past location
The lorries would have taken the back lane; the ford was up.: reconstruction of a past choice
Anyone would have noticed the cracked hoop.: a general claim about the past, slightly critical
He wouldn't have left the press running on purpose.: negative speculation about intention

This would have is close to might have, but more committed. Might have keeps the guess open; would have treats the reconstruction as the expected past.

How Will Have and Would Have Work

The same have plus participle, aimed at two different times.

Will Have Stands at a Later Deadline

From a future point you look back and treat the action as already complete. By dusk, by Friday, by the time the cooper arrives, and in October all name that point. The participle never changes; will have does the work of locating you. This is the same idea as the future perfect tense, stripped here to the modal string and set beside would have.

By the time the lorry comes, we will have hooped every barrel.

hooping is complete before the lorry's arrival

By X, will have done.

Will Have Also Infers the Present

Move the deadline to now and the same string becomes a deduction: They'll have stacked the crates by now. You are not waiting for a future moment; you are reading present evidence and stating what must already be true. Won't have does the negative version: She won't have locked up yet.

Don't walk through the mill; they'll have washed the floor.

present caution based on an inferred completed action

By now, they'll have done it.

Would Have Is an Unreal Past Result

Would have plus a participle is the result half of the third conditional. The condition sits in the past perfect (if the mill hadn't jammed) because that event did not happen the way you needed. The result is equally unreal: we did not finish sooner. The form comments on a closed past, which is why it also carries regret, relief, and criticism.

If we had started at dawn, we would have pressed the whole crop.

we did not start at dawn, so we did not press it all

If I had..., I would have...

Would Have Also Speculates without If

The same string can reconstruct a past without spelling out a condition. She would have taken the upper path is a guess about what happened. Anyone would have noticed the cracked hoop is a claim about what a reasonable person would have done. Context decides whether you are in a conditional or in speculation.

The lorries would have used the back lane in that flood.

a reconstruction, no if-clause needed

Would have = expected past, often a guess.

Never Put Would Have in the If-Clause

The if-clause of a third conditional takes the past perfect, not would have. If I would have checked the belts is a common learner form and is not standard. Keep would have for the result (or for speculation), and keep had plus a participle for the condition.

If she had checked the belts, the mill would have run.

had checked in the if-clause, would have run in the result

If I had..., not if I would have...

Common Mistakes with Will Have and Would Have

Incorrect: If I would have checked the belts, the mill would have run.

Correct: If I had checked the belts, the mill would have run.

The if-clause of a third conditional takes the past perfect. Would have belongs only in the result. If I would have is a common spoken form and is not standard in writing.

Incorrect: By dusk we would have pressed the last apples, so start stacking the crates.

Correct: By dusk we will have pressed the last apples, so start stacking the crates.

The deadline is still ahead and the instruction is real. Would have would turn the sentence into a regret about a past dusk.

Incorrect: They will have stacked the crates yesterday.

Correct: They stacked the crates yesterday. / They will have stacked the crates by now.

Will have cannot combine with a finished-time word like yesterday. Either tell the past with the past simple, or keep will have with by now, already, or a future deadline.

Incorrect: We would have finish sooner if the mill hadn't jammed.

Correct: We would have finished sooner if the mill hadn't jammed.

Would have needs a past participle, not a base verb. Finish has to become finished, just as press becomes pressed and take becomes taken.

Won't Have and Wouldn't Have

The negatives split the same way the positives do, and one extra reading appears.

Won't have

Won't have plus a participle either misses a future deadline or denies a present deduction.

We won't have bottled the vat by Friday.: deadline will not be met
She won't have locked up yet; the lights are on.: negative deduction about now
They won't have heard the forecast out in the orchard.: a present assumption about what has not happened

The lights-are-on sentence is the mirror of they'll have locked up: same evidence, opposite conclusion.

Wouldn't have

Wouldn't have plus a participle denies an imagined past result, or rejects a past intention.

I wouldn't have left the press running.: that is not something I would have done
We wouldn't have lost the russets if we'd netted the trees.: negative third-conditional result
He wouldn't have taken the ford in that flood.: speculation that rules a past choice out

I wouldn't have thought plus a clause is a fixed comment meaning I'm surprised: I wouldn't have thought the mill could jam so quietly.

Quick Check: Will Have and Would Have

Choose will have or would have and put the verb in the past participle.

1. By Friday they ___ (bottle) the first vat.

Answer: will have bottled

future deadline still ahead

2. They ___ (stack) the crates by now; the yard is empty.

Answer: will have stacked

deduction about the present

3. We ___ (finish) sooner if the mill hadn't jammed.

Answer: would have finished

third-conditional result

4. If she ___ (check) the belts, the mill would have run all morning.

Answer: had checked

if-clause takes the past perfect, not would have

5. I ___ (leave) the press running; that isn't something I do.

Answer: wouldn't have left

negative speculation about a past action

Will Have and Would Have FAQs

What does will have mean?: Will have plus a past participle means the action is complete before a point you are looking at. That point can still be ahead (By dusk we will have pressed the last apples) or it can be now (They'll have stacked the crates by now). The first is a completed future; the second is a deduction from present evidence.
What is the difference between will have and would have?: Will have aims at a real later deadline or infers a real present. Would have aims at a past that did not happen, usually the result of a third conditional: We would have finished sooner if the mill hadn't jammed. Swap them and a plan becomes a regret. They share have plus a participle and nothing else of their time reference.
Is will have the same as the future perfect tense?: It is the same string. The future-perfect page treats the tense as a system, with duration (In October I will have kept bees for twenty years) and by-phrases. This page sets that string beside would have, so you can see the pair: completed future versus imagined past. Use either page depending on which neighbour you need.
Can I say if I would have instead of if I had?: Not in standard English. The if-clause of a third conditional takes the past perfect: If I had checked the belts, the mill would have run. Would have stays in the result. If I would have checked is widely heard in speech and is still marked as an error in careful writing.
How is would have different from must have or might have?: Must have is a confident deduction from evidence (The floor is wet; they must have washed it). Might have is an open past possibility. Would have is either an unreal past result or a reconstruction you treat as the expected past (She would have taken the upper path). All three take have plus a participle; the modal is what changes the job.