Could vs. May

'Could' and 'may' are modal verbs that are often mistaken since they are both used to ask for permission. In this lesson, we will learn when to use them.

"Could" vs. "May" in the English grammar

What Is Their Main Difference?

The main difference between 'could' and 'may' is that 'may' is politer and is used in formal contexts.

'Could' is one of the most commonly known modal verbs. It helps us talk about abilities, ask for permission, request something, offer things, etc. We use it to refer to the past. In other words, 'could' is the past tense of modal verb 'can.' Have a look:

I could have another slice of Pizza.

Here, we are talking about abilities.

Could you give me hand?

Here, we are requesting something.

'May' is another modal verb manly used to talk about possibilities, give and ask for permissions, etc. Consider the following examples:

I may attend the party tonight.

Here, we are talking about possibilities.

You may leave the class.

Here, we are giving permission.


Giving and Asking for Permission

We use 'could' and 'may' are used to give and ask for permission.

Giving Permission

Both 'may' and 'could' are used to give permission. 'May' is much politer and more formal than 'could.' Compare:

You may go out today.

You could use my car anytime.

Asking for Permission

'May' and 'could' are used in the present time to ask for permission. 'May' is politer than 'could' and therefore it is mainly used when talking to authorities. For example:

May I use my phone?

Could I borrow your car for today?

Talking about Possibilities

We use 'may' and 'could' to refer to something we are not certain about their chance of occurrence.
'Could' is used to refer to past, present, and future events that had or still have a chance of happening.

She could win the prize.

We could have flying cars in the future.

'May' is also used to show a chance of occurrence in the present and the future.

She may win the prize.

We may have flying cars in the future.

Making Offers

Offers are statements that help us show that we are ready and willing to do something for someone. We use 'could' and 'may' to make such offers.
'Could' is not past tense, when we are offering something. Offers that are made with 'could' are less definite than other forms of offers. Meaning that the offer is made but we are uncertain if the listener will accept or not.
When making offers with 'may,' we use a first-person singular or plural pronoun (I and we).
Note that 'may' is more formal than 'could.'
For instance:

Could I give you a piece of advice?

May I give you a piece of advice?

Negation and Question

As modal verbs, 'could' and 'may' are subjects of change when creating negative sentences. To make them negative, we add 'not' to them as shown below:

  • CouldCould notCouldn't
  • MayMay not

Here are some examples:

I could sing. → I couldn't sing.

I may leave the country. → I may not leave the country.

Modal verbs are inverted when we are creating a question. Watch:

I may go to the mall. → May I go to the mall?

I could read all day. → Could I read all day?

With Other Modals

We only have one modal verb in a sentence and we cannot add more than one modal verb to a sentence. Have a look:

I may would leave for California tomorrow.

She shall could borrow my notebook.


Giving Advice

We use the modal verb 'could' to give advice and express our opinion on how something could be better. We often use 'could' to show our disapproval of something. Since 'could' is past tense, it means that situation we are talking about has already happened and there is no way of changing it. For instance:

You could be more careful to avoid such accidents.

He could get help from the internet to answer the questions.

Expressing Wishes

We use 'may' to talk about our wishes, prayers, or hopes. In this function, 'may' is often placed at the beginning of the sentence. For instance:

May her soul rest in peace.

May all of your wishes come true.

Talking about Abilities

We use 'could' to talk about past abilities. This means that the ability, talent, or skill existed before but it no longer exists or is not used anymore. Take a look at the following examples:

She could run really fast before the accident.

I could jump really high when I was younger.


'May' is more formal than 'could.' In formal contexts, it is advised to use 'may' to show gratitude and respect. Have a look:

May I ask a question?

Could I ask a question?

With Conditionals

'Could' and 'may' are modal verbs that can be used as conditional verbs.

Conditional Type 1

'May' and 'could' are both used in conditionals type 1. In this type, we show a condition and its results. These conditions are real situations with a high chance of occurrence.

If you promise to be careful, I may let you drive.

You could lose weight, if you work out every day.

Conditional Type 2

Conditional type 2 talks about hypothetical situations. These situations are imaginary and unlikely to happen in the present or future. The chance of these situations becoming real is very low. We use modal verb 'could' to talk about these situations.

If I were rich, I could buy a house in the woods.

He could move out if he saved enough money.

Conditional Type 3

Conditional type 3 is the only conditional that talks about the past. This type talks about hypothetical situations in the past. In other words, we are describing a different past or a different outcome from past events.

If I studied harder, I could have gone to university

If I had won the lottery, I could have bought a house.


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