Difference Between Would Have and Could Have

Introduction

‘Crying over spilt milk’ is an old proverb that emphasizes the fact that what is done is done. One cannot turn back time. No matter how hard you try or cry, in this case, what has already happened cannot be changed. That argument where you made a fool of yourself or the time you wore the same dress as your colleague at a work event or when you were called upon in class but did not have an answer as to which nations formed the axis forces in the world war because you dozed off for that split second because last night’s movie could not be missed… the embarrassment of having the wide-eyed stares of your classmates or colleagues zeroed on you, secretly laughing at you while you wish the earth would just split open and engulf you in it. Well, that also does not happen.

No matter how many times you wish for the earth to reverse its rotation, it is pointless. Even the time stone from the famous Marvel comics does not exist in actuality. And even if it does, Doctor Strange guards it with his life and uses it only to help fellow superheroes like Spider-Man. Real or not, time is a hard taskmaster. Once it has passed, though, one can talk about it and relive the shame. If not to dwell in it, only to learn from it.

Would Have vs. Could Have

While one dwells in the past, they use modal verbs like ‘would have’ and ‘could have’ along with a past participle. Modal verbs are verbs that show intent and possibility. Past modal verbs like ‘would have’ and ‘could have’ indicate the present feelings of an event that has already occurred in the past. To form past modals, the modal verbs ‘would’ and ‘could’ must be followed by ‘have’. They can never be followed by ‘has’ or ‘had’. While ‘would have’ and ‘could have’ both indicate a possibility, ‘could have’ is used in sentences that mean that something was possible but did not happen. ‘Would have’ is generally used in sentences that mean one wished for something to happen that didn’t. it has a more unreal quality in that, it is used where one hopes for a different outcome.  Let us see the differences.

Differences Between ‘Would Have’ and ‘Could Have’ in a Tabular Form

PARAMETER	WOULD HAVE	COULD HAVE
Purpose	‘Would have’ is often used in sentences that are of incidents that have taken place in the past. It is used to express a wish for a different result.	‘Could have’ is also used in sentences that are of past events. It is used to discuss the possible outcomes or happenings of the event.
Situation	‘Would have’ is used in a wishful sense.	‘Could have’ is used to talk of practical possibilities.
Usage	‘Would have’ is usually used to make offers and invites.	‘Could have’ is usually used in offering a suggestion, making a request or seeking permission.
Indication	‘Would have’ indicates a possibility in a sentence. It is used in a conditional.	‘Could have’ indicates the ability in a sentence.
Example	I would have come to the party is I was in town.	I could have completed the assignment if I had my computer.
Contraction	The contraction of ‘would have’ is ‘would’ve’.	The contraction of ‘could have’ is ‘could’ve’.
Negative contraction	The negative contraction of ‘would have’ is ‘wouldn’t have’	The negative contraction of ‘could have’ is ‘couldn’t have’

When to use ‘Would Have’?

‘Would have’ is a modal verb that is used hypothetically – when talking of or hoping for an outcome that was possible but didn’t happen. It is used in sentences where one talks of imagined scenarios or where one is wishful of a different outcome. It has two structures. They are as follows:

• Since ‘would’ is used to indicate volition, ‘would have’ is used to show something that one wanted or did not want to do. In such a case, there is no ‘if’ clause required. This structure uses the word ‘but’ so the sentence has the following structure – I would have A, but I had to B. Here A and B are the actions performed.

For example:

I would have participated in the marathon but I slept in instead.

I would have given you my coat but I don’t have it on me.

• The second structure is one where the clause is of a past unreal conditional. Past unreal conditionals are sentences that are often used to express wishes or regrets of the past. They are usually filled with sorrow. They show that a person wishes to have acted differently than they had at that moment.

For example:

I would have made another dessert had I known there were going to be kids.

I would have saved more money if I knew we would spend it all on a play station.

Other examples of the use of ‘would have’:

In an affirmative sentence:

I would have gotten an umbrella if you had informed me earlier of the storm.

In a negative sentence:

She wouldn’t have excelled at the test were it not for your training.

(Note here that the contracted form ‘wouldn’t’ is more commonly used than ‘would not’. Also, the word ‘not’ always comes between ‘would’ and ‘have’ in a negative sentence. It cannot be used after have. ‘Would have not’ is incorrect.)

In an interrogative sentence:

Here, the subject and verb order is reversed.

For example, in an affirmative sentence – They would have brought butter for the bread if we had asked them to. The subject is ‘they’ and ‘would’ is the modal verb and the subject comes before the verb. Contrarily, in an interrogative sentence, the sentence would be - Would/ wouldn’t they have brought some butter for the bread, had we asked them to? – here, the verb (would/ wouldn’t) comes before the subject (they).

In all these sentences ‘would have’ is used in the past form and indicates a wishful or an alternative outcome.

When to use ‘Could Have’?

‘Could have’ is also used in the hypothetical sense where one talks of things that didn’t happen. It is generally used to speak about the possibilities of an event that did not come to pass due to an unexpected difficulty. These possibilities are more practical than imagined or unreal. It can also be structured in 2 ways. They are as follows:

• ‘Could have’ + past participle – Here, the use of ‘could have’ indicates that something was possible in the past but it did not happen because one chose to act differently. In such a case, ‘could’ becomes a modal of ability. Such a verb is used to show that a person is either capable or incapable (negative sentence) of performing a function. Examples of the use of ‘could have’ as a modal of ability:

He could have come sooner, but he chose to stay back.

She could have bought the salad, but she decided to cook instead.

Similarly, the negative contraction ‘couldn’t have’ can be used. But using ‘couldn’t have’ means that something wasn’t possible in the past. Even if one had tried to accomplish the task to the best ability. For example:

He couldn’t have come any sooner. There was a massive roadblock.

She couldn’t have bought the salad. It was rotten and stinky.

• ‘Could have’ + past participle can also be used to indicate a probability. It is used to make a possible guess about something that happened in the past. In such a case, there is no certainty if the sentence is true or not. It is more about the opinion of the person making the statement. Here, ‘could have’ is used as a modal of probability. Such a verb is used to make a guess. For example, if looking for an answer as to why a person was late to a meeting – he could have forgotten about the meeting or he could have had a fall on the way up to the room or he could have overslept.

Examples of the use of ‘could have’:

In an affirmative sentence:

I could have scored higher if I had studied harder

In a negative sentence:

She couldn’t have brought the pup home since it belonged to her boss.

(Again, it is important to note here that the contracted form ‘couldn’t’ is more commonly used than ‘could not’. Also, the word ‘not’ always comes between ‘could’ and ‘have’ in a negative sentence. It cannot be used after have. ‘Could have not’ is incorrect.)

In an interrogative sentence:

Here, as well, the subject and verb order is reversed.

For example, in an affirmative sentence – He could have known about the secret before she revealed it. The subject is ‘he’ and ‘could’ is the modal verb and the subject comes before the verb. Contrarily, in an interrogative sentence, the sentence would be - Could/ couldn’t he have known about the secret before she revealed it? – here, the verb (could/ couldn’t) comes before the subject (he).

In all these cases, ‘could have’ indicates a possibility rather than a wishful outcome.

Differences Between ‘Would Have’ and ‘Could Have’ in points

Following are the main differences between ‘would have’ and ‘could have’:

1. ‘Would have’ is used in sentences of past events where one wishes for a different outcome whereas ‘could have’ is used in sentences of past events where there are different outcomes possible.
2. When using ‘would have’ the possibilities are ureal or imagined while when using ‘could have’, the possibilities are real.
3. ‘Would have’ demonstrates possibility in a sentence and is mostly used as a conditional. On the other hand, ‘could have’ demonstrates ability or probability in a sentence.
4. ‘Would have’ is generally used when one talks of requests and permissions while ‘could have’ is generally used for offering suggestions.
5. An example of a sentence with ‘would have’ is as follows – I would have come home sooner if it were not for the rain. An example of a sentence with ‘could have’ is as follows – I could have brought home more chocolates if I had a bigger bag.
6. An example of a negative sentence with ‘wouldn’t have’ is as follows – I wouldn’t have come if I had known the pig would be here. An example of a negative sentence with ‘Couldn’t have’ is as follows – ‘He couldn’t have known about the disaster since he was busy.’
7. An example of an interrogative sentence with ‘would/ wouldn’t have’ is as follows – Would/ wouldn’t she have learnt to swim at the camp? An example of an interrogative sentence with ‘could/ couldn’t have’ is as follows – Could/ couldn’t he have swum faster without the floats?
8. ‘Would have’ is used more for offers and invites while ‘could have’ is used more for suggestions.

Conclusion

Since the past cannot be changed, it is no use trying to make it happen. But we can sure talk about it. To do so, we can use the modal verbs – ‘would have’ and ‘could have’. These are also known as modals of lost opportunities. They are known to work like a grammatical time machine. A sentence in the simple past tense only conveys what happened. Past modals can make it more interesting by telling us what would have or could have happened. ‘Would have’ is generally used to express an imagined result. For example – ‘I would have saved the yoghurt but it was past its expiration date.’ ‘Would have’ is also used to make offers and invitations and is considered more informal.

‘Could have’ on the other hand, is used in sentences when expressing that something possible did not occur. It is used either as a modal of ability or a modal of probability. As a modal of ability, an example is as follows – ‘He could have drawn that picture of a flower.’ As a modal of probability, an example of an answer to the question of why a flower petal fell, is as follows – ‘it could have been the wind that blew off the petal’. ‘Could have’ is also used while seeking permissions or making suggestions and is also considered more formal.

Both ‘would have’ and ‘could have’ have the intention of giving possibilities. Even if they are mere imaginations or suppositions. To make those possibilities real, we still need the Time stone or a time machine. Until then, though, let us satiate our quest for the past not by drowning in our sea of regrets or embarrassments but by learning from those mistakes and coming out stronger. 

References

1. https://learningenglish.voanews.com/a/everyday-grammar-could-have-should-have-would-have/3391128.html
2. https://www.perfect-english-grammar.com/could-have-should-have-would-have.html
3. https://www.espressoenglish.net/past-modals-should-have-could-have-would-have/