Third Conditional: Form, Uses and Examples
The third conditional lets you imagine a different past: if I had left earlier, I would have caught the train. Use it for regrets, criticism and relief about things that cannot change now.
By LearnLingo Team · Updated
Form
| Type | If clause (past perfect) | Result clause | Example |
|---|---|---|---|
| Affirmative | If + had + past participle | would have + past participle | If you had asked me, I would have helped. |
| Negative | If + hadn't + past participle | wouldn't have + past participle | If it hadn't rained, we wouldn't have stayed home. |
| Question | If + had + past participle | would + subject + have + past participle? | What would you have done if you had lost your passport? |
| Possible result | If + had + past participle | could have, might have + past participle | If we had hurried, we might have caught the bus. |
The two clauses can go in either order. Use a comma when the if clause comes first: If I had known, I would have come. No comma is needed when it comes second: I would have come if I had known.
| Full form | Spoken short form | Note |
|---|---|---|
| If I had known | If I'd known | In the if clause, 'd means had. |
| I would have come | I'd have come | In the result clause, 'd means would. |
| would have | would've | Sounds like wood-uv. Never write would of. |
| would not have | wouldn't have, wouldn't've | Wouldn't've is spoken, not written. |
| could have, might have | could've, might've | Same weak have sound. |
So If I'd known, I'd have come means the same as If I had known, I would have come. In fast speech have is pronounced ⁄əv⁄ or even ⁄ə⁄.
| Conditional | Time | Form | Example |
|---|---|---|---|
| Zero | always true | If + present, present | If you heat ice, it melts. |
| First | real future | If + present, will | If it rains, I'll stay in. |
| Second | unreal present or future | If + past, would | If I had more money, I'd travel. |
| Third | unreal past | If + past perfect, would have | If I had saved money, I'd have travelled. |
How to make the third conditional
The third conditional has two parts. The if clause uses the past perfect: had + past participle. The result clause uses would have + past participle. Both parts describe things that did not happen.
If I had seen you, I would have said hello means I did not see you, so I did not say hello. You need the correct past participle, so check irregular verbs like seen, gone, known and taken.
Do not put would in the if clause. Say If I had known, not If I would have known. This is one of the most common mistakes at this level, even among native speakers in casual speech, but it is not accepted in standard English.
If I had known about the party, I would have come.
She would have won the race if she hadn't fallen.
If they had taken a taxi, they wouldn't have been late.
What would you have done if the bank had said no?
Regrets and criticism
We often use the third conditional to talk about regrets: things we wish we had done differently. The meaning is: the past cannot change, but I can imagine another version of it.
It is also used to criticise, gently or strongly. If you had listened to me, this wouldn't have happened is a classic complaint. For the same feeling in a shorter form, English also uses wish and if only: I wish I had listened, If only I had listened.
If I had studied harder, I would have passed the exam.
We would have saved a lot of money if we had booked earlier.
If you had told me the truth, I wouldn't have been so angry.
If I'd known it was your birthday, I'd have bought you something.
The first 'd is had and the second 'd is would.
Relief and imagined consequences
The third conditional is not only for bad things. We also use it to show relief or gratitude: something bad did not happen because of a lucky event or another person's help.
Use could have to talk about ability or possibility, and might have when you are less sure about the result. If it hadn't been for you, I would never have finished is a common way to thank someone. See modal perfects for more about could have and might have.
If the doctor hadn't acted so quickly, he could have died.
If we had left five minutes later, we might have missed the flight.
If it hadn't been for your help, I would never have finished.
If she hadn't moved to London, she wouldn't have met her husband.
Without if: inversion and but for
In formal English, you can drop if and put had before the subject: Had I known, I would have come. This means exactly the same as If I had known. The negative is Had I not known, never Hadn't I known.
Another formal pattern is but for + noun: But for the rain, the match would have been finished (if it had not been for the rain). In everyday speech, the if version is far more common.
Had we known about the strike, we would have driven.
Formal: If we had known.
Had she not called, I would have forgotten the meeting.
But for his quick thinking, the fire would have spread.
Third conditional or second conditional?
The second conditional imagines the present or future: If I had a car, I would drive to work (I do not have a car now). The third conditional imagines the past: If I had had a car, I would have driven to work (I did not have one then).
The form had had looks strange, but it is correct: the first had is the past perfect helper and the second is the past participle of have. When the past condition has a present result, you need a mixed conditional: If I had taken the job, I would be rich now.
If I knew her number, I would call her.
Second conditional: I don't know it now.
If I had known her number, I would have called her.
Third conditional: I didn't know it then.
If he had had more time, he would have checked his work.
In real life
In speech, the third conditional is almost always contracted. Listen for If I'd known and I'd have, would've and wouldn't have. Native speakers often say it very fast: If I'd known, I'd've come. Learn to hear the weak have sound, and in writing always spell it have, never of.
Short reactions are common too: I would have! (meaning I would have done it), You should have told me, I'd never have guessed. These short forms show regret or surprise in a natural way.
Why didn't you call me? I'd have picked you up.
If I'd known it was this cold, I'd have brought a coat.
Wow, I'd never have guessed you were forty.
It would've been easier if you'd asked for help.
If we hadn't got lost, we'd have been here an hour ago.
American English often uses gotten: hadn't gotten lost.
Common mistakes
If I would have known, I would have come.
If I had known, I would have come.
Would does not go in the if clause. The if clause uses the past perfect, had + past participle.
I would of helped you.
I would have helped you.
Would've sounds like would of, but the written form is always have.
If I had studied, I would passed.
If I had studied, I would have passed.
The result clause needs all three parts: would + have + past participle.
If she had came earlier, she would have seen him.
If she had come earlier, she would have seen him.
After had, use the past participle, not the past simple. Come is irregular: came is the past simple and come is the past participle.
Hadn't I missed the bus, I would have been on time.
Had I not missed the bus, I would have been on time.
In the inverted form, the negative is Had + subject + not. Hadn't I is used only in questions.
Practice quiz
10 questions. Pick an answer to see if it is right and why.
1. If I ___ the alarm, I wouldn't have been late.
2. If you had asked, I ___ you.
3. Choose the correct sentence.
4. What does If we had left earlier, we would have caught the train mean?
5. In I'd have called you if I'd known, what do the two 'd forms mean?
6. If it ___ for your help, I would have failed.
7. ___ the email, I would have replied sooner.
8. Which sentence talks about the past?
9. If we hadn't stopped for coffee, we ___ the accident.
10. Choose the correct written form.
0 of 10 answered
Show all answers
- had heard
- would have helped
- If she had seen it, she would have told me.
- We didn't leave early and we missed the train.
- would, had
- hadn't been
- Had I seen
- If I'd had a car, I'd have driven.
- might have seen
- She could've won.
See what the B2 English course covers, or test your level first.
People also ask
When do we use the third conditional?+
We use it to imagine a past that did not happen and its result: regrets (If I had saved, I would have bought it), criticism, relief and speculation about the past. Both the condition and the result are unreal because the past cannot change.
Can I use would in both clauses of the third conditional?+
In standard English, no. Only the result clause has would have. You may hear If I would have known in casual American speech, but it is considered incorrect in writing and in exams.
What is the difference between would have, could have and might have?+
Would have shows the result you are sure about. Could have shows that the result was possible or that someone would have been able to do it. Might have shows a less certain possibility.
Why is it had had in some sentences?+
When the main verb is have, the past perfect is had had: If I had had time, I would have called. The first had is the helper verb and the second is the past participle of have.
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