“Can I” or “May I”? Which should we use?

When we ask for, give, and refuse permission, the words we most often use are can and can’t:

  • Can I speak to Dave Williams, please?
  • You can help yourselves to tea and coffee.
  • I’m sorry, you can’t smoke here.

You’ve probably also heard may used in requests and when giving/refusing permission:

  • May I take a message?
  • Passengers may not leave the airport while waiting for a connecting flight.

So what’s the difference between can and may in requests?

1. May is more formal than can when asking for and giving permission:

  • May I speak to Mr Jones, please?

2. We use may when we want to sound more polite:

  • May I offer you another drink, sir?

3. We see or hear may, not can, in official announcements, and on signs:

  • Hotel guests may use the gym from 6 a.m.

May vs. can = formal vs. informal

Look at the difference between these two signs:

may vs can: formal / informal permission

Watch out! Although we very often shorten cannot to can’t, the contraction mayn’t (may not) is rarely used nowadays. Stick with can’t in spoken English when you refuse permission or say that something isn’t allowed.

For more examples, see Grammar rules: modal verbs for expressing permission, or take a look at this British Council page, which has some example sentences.

Feel free to ask questions in the comments below!

Stuart is an English teacher and runs the Speakspeak website. He currently lives in Prague and has been teaching for over 20 years. Follow Stuart and contact him by subscribing to his monthly newsletter.

7 Comments

  1. Farhan - September 9, 2013, 9:07 pm Reply

    Thanks for this useful lesson….

  2. Marco Pugliesi - September 12, 2013, 7:27 pm Reply

    Great advice

  3. cent m - October 17, 2013, 11:44 am Reply

    thanks for this wonderful artiacle

  4. Rachel - March 17, 2014, 8:02 am Reply

    I was taught that MAY refers to permission, whilst CAN refers to ability.

    For example:
    Question
    “Can I go to the bathroom?”

    Response
    “Yes, you can go to the bathroom but you may not go now”.

    • Stuart Cook - March 17, 2014, 8:36 am Reply

      Hi, Rachel

      I think the example of the response you can . . . but you may not . . . would work well only as a sarcastic or witty remark. In everyday modern usage, can and may both express permission, except with different levels of formality. I do appreciate that this usage can differ slightly in the US, though.

      Don’t forget that a single modal verb often expresses several different things. Take can as an example:
      I can swim. (ability)
      I can swim if I want to. (possibility)
      She can’t be swimming – her bathing costume is here. (deduction)

      • Rachel - March 17, 2014, 9:41 am Reply

        Hi Stuart,

        great to see such a prompt response.

        When I was at school it was a common practice to use the witty response to highlight the difference to children.

        I do understand that the two can be used interchangeably in respect to permission, however, your article was titled ‘“Can I” or “May I”? Which should we use?’.
        You only mention that they’re interchangeable in the respect to permissions. If it was in terms of ability the answer is they are different and not interchangeable.
        I think that you should elucidate on the differences of the two words so that someone who is trying to learn doesn’t blindly use may when they should be using can.

  5. Rose - August 9, 2016, 10:13 pm Reply

    Thank you, teacher Stuart, it was exatelly that I was looking for.

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