Can vs Could: Difference and Comparison

The ability or a doing cannot be described without a verb, and helping verbs play a crucial role. There are two types of helping verbs; modal verbs and auxiliary verbs.

“Can” and “could” are examples of these two types of verbs. The former is used in the present, while the latter is a past form of ‘can.’

Key Takeaways

1. Can refer to the present ability to do something, while it could refer to the past ability or possibility of doing something.
2. Can is used to talk about general ability or permission, while could is used to talk about specific abilities or possibilities in the past.
3. Can is used to make requests or ask for permission, while could is used to make suggestions, give advice, or show politeness in a formal situation.

Can vs Could

Can” expresses ability in the present, as in “I can swim.” It can also be used to express permission, as in, “Can I go to the bathroom?” “Could” expresses ability in the past, as in “I could swim when I was younger.” It can also express possibility or a polite request, such as, “Could you pass the salt?

Can literally mean “to be able to do something”; sometimes even “permitted to carry out a task.” To talk or describe one’s ability to do something in the present, ‘can’ is used.

For example, “I can dance” or “Can you pick up the pen?”

Even though ‘could’ is the same as ‘can,’ it is used to talk about someone’s past ability to do/carry out a task.

It can also be used to talk about the present ability of an individual to do something but might not do it.

For example, “The earthquake could have been worse” or “The food could have tasted better.

Comparison Table

Parameters of Comparison	Can	Could
Meaning	The word “can” refers to being able to do something.	The word “could” means the ability or possibility of doing something.
Type of verb	Modal verb	A modal and auxiliary verb
Type of possibility	It shows a strong possibility.	It shows the weak possibility.
Ability	Present	Past
Tone	Informal	Polite

What is Can?

The verb “can” is a modal verb, a very base form of the verb. It is most commonly used while speaking or writing English.

It is used to portray a present situation. It expresses an ability or a possibility. 

It is also used to tell someone they can do something.

Except for conveying the ability of someone to do something, “can” is also used to seek permission, to request, to convey a possibility and opportunity.

The examples for the uses mentioned above are as follows:

1. Ability: I can make music and dance too.
2. Permission: Can you lend me a pen?
3. Request: Can you help me in completing an assignment?
4. Possibility: You can be the winner.
5. Offer: Can I help you to cross the road?

It can also be used to ask a polite question only when seeking permission to do or say something.

What is Could?

The verb “could” is an auxiliary verb that is a past participle of “can”. It depicts the past ability of someone to do something that may or may not have occurred.

It refers to something you believe in or know will take place.

Along with past ability, it can also be used to convey a potential possibility; “could” can also be used as the future tense of “can.

Moreover, it can be used to suggest something, ask for permission, and be a conditional form of “can”. 

The examples for the above statement are given below:

1. Ability: I could sing well when I was younger.
2. Possibility: You could get good marks this time.
3. Suggestion: He could rewrite and fix the mistakes.
4. Permission: Could you pass me the file?
5. Conditional form of “can”: I could make you dinner if you told me what you want to have.

Main Differences Between Can and Could

1. The word ‘can’ points out a thing or person’s ability to do something. On the other hand, the word ‘could’ is used to express a past ability of someone to do something.
2. The word ‘could’ is used when there is uncertainty in the occurrence of a specific situation, while the word ‘can’ assures the occurrence. In other words, ‘could’ represents a weak possibility, whereas ‘can’ represents a strong possibility of an event.
3. ‘Can’ states present situations, i.e., in the present tense. On the contrary, ‘could’ is used as a past tense of “can. For example, I can write articles. (fact); I wish I could write articles (in the future)
4. The verb ‘can’ is a modal verb; its usage is followed by the main verb stating a fact, whereas the verb ‘could’ is a past form of can/ past participle used with the main verb to state a past ability of someone.
5. Even though the uses of both words are similar, their tones are different. Can’ sounds more informal, while the other has a formal, polite tone. The former is used while talking to friends or relatives, whereas the latter is used while talking to professionals, elders, or strangers.