Difference Wiki

Could vs. May: What's the Difference?

Edited by Harlon Moss || By Janet White || Published on December 12, 2023
"Could" is used to express possibility or past ability, while "may" indicates permission or a higher likelihood of occurrence.

Key Differences

"Could" is often used to suggest a possibility that is more hypothetical or uncertain, while "may" suggests a possibility that is more likely or real.
"Could" is used to talk about someone's ability in the past, whereas "may" does not have a function related to ability.
"May" is traditionally used to ask for or give permission, reflecting a more formal or polite tone. "Could," in contrast, can be used for permission but is less formal.
When talking about the likelihood of events, "may" implies a greater probability than "could." "Could" is often used in speculative situations.
"May" is generally more formal and polite than "could." The use of "may" in formal requests or permissions is common, while "could" is often used in more casual or informal contexts.

Comparison Chart


Indicates possibility or past ability
Indicates permission or likelihood


Less formal, more hypothetical
More formal, indicates higher likelihood


Often used in speculative or hypothetical scenarios
Used in formal requests or permissions

Expressing Ability

Refers to past abilities
Not used for expressing ability


Implies lower probability
Implies higher probability or possibility

Could and May Definitions


Past Ability.
She could play the piano when she was younger.


Formal Request.
May I have your attention, please?


Polite Request.
Could you please pass the salt?


It may rain later today.


It could rain tomorrow.


Expressing Wishes.
May you have a prosperous New Year.


Hypothetical Situations.
If I had time, I could learn Spanish.


May I leave the table?


Suggesting Options.
You could try calling the helpline.


Speculative Statements.
The results may vary depending on the data.


Inflection of can


A hawthorn or its blossoms.


Used as a past subjunctive (contrary to fact).
I think he could do it if he really wanted to.
I wish I could fly!


The fifth month of the year in the Gregorian calendar. See Table at calendar.


Can 'could' be used for requests?

Yes, but it's less formal than 'may.'

When is 'may' used?

For permission or indicating likelihood.

Can 'could' suggest options?

Yes, like "You could try this method."

Can 'may' indicate probability?

Yes, it often suggests higher likelihood.

How is 'may' used in wishes?

As in "May you have a good trip."

Does 'could' imply certainty?

No, it implies uncertainty or hypothetical situations.

Is 'could' suitable for formal situations?

Less so, 'may' is preferred in formal contexts.

Is 'may' formal for permission?

Yes, it's more formal and polite.

What is 'could' mainly used for?

To express possibility or past ability.

Does 'may' have a past tense form?

No, it's primarily present tense.

Is 'may' used for expressing wishes?

Yes, especially in formal or traditional contexts.

Can 'may' be used in speculative statements?

Yes, for example, "The results may vary."

What indicates a lower probability, 'could' or 'may'?

'Could' usually indicates lower probability.

What's the main difference in usage between 'could' and 'may'?

'Could' is for hypotheticals and past ability, 'may' for permission and likelihood.

Does 'may' express past abilities?

No, that's a function of 'could.'

Is 'could' appropriate for polite requests?

Yes, but 'may' is more formal.

In what context is 'could' more speculative?

In scenarios that are less likely or uncertain.

Can 'could' be used for future possibilities?

Yes, like "It could happen tomorrow."

How does 'could' express hypotheticals?

Through conditional sentences, like "If I had time, I could..."

How is 'may' used in formal requests?

As in "May I speak to the manager?"
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.

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