Can and may both help us talk about what is possible. The traditional rule is simple: can is for ability, and may is for permission or a chance something will happen.
- Can: I can swim. (I am able to)
- May: May I go outside? (Is it allowed?) It may rain. (Maybe it will)
Can: ability
Use can for what you are able to do.
I can ride a bike.
Mia can speak two languages.
Birds can fly, but penguins cannot.
Can you hear the music?
May: permission and possibility
Use may to ask or give permission, and to say something might happen.
May I borrow your pencil?
You may go home now.
It may snow tomorrow.
Sam may be late, because the bus is slow.
Easy way to tell them apart
Ask: am I talking about being able, or about being allowed?
- Able to do it? Use can.
- Allowed to do it, or maybe it will happen? Use may.
Can I lift this box? (Am I strong enough?)
May I lift this box? (Is it OK for me to?)
💡 The OddLingo Trick
The word may has the letters of maybe inside it. So may is the word for "maybe" and "is it OK?".
For can, think of can-do. If you are able to, you can.
⚠️ Common Mistakes
May is not for ability.
❌ I may swim very fast.
✅ I can swim very fast.
Do not add to after can or may.
❌ Can I to go out?
✅ Can I go out? / May I go out?
Can has no -s.
❌ She cans sing.
✅ She can sing.
📌 Good to know
- Cannot is usually one word, and the short form is can't. For may not, just say may not.
- The old rule is neat, but real life is looser. In everyday talk, many people ask Can I...? for permission, and that is widely accepted.
- May is often a little more polite and formal. A teacher might like May I...? in class.
- Long ago, may meant "to have power or be able", and can meant "to know". The meanings moved over time, and can for permission is only about 150 years old.
- For possibility, might is also common: It might rain.
💬 In a Conversation
Mia: Can I have some juice?
Teacher: You are able to. But are you allowed?
Mia: May I have some juice, please?
Teacher: Yes, you may.
Mia: That was a very polite way to get juice.