Use may I when you want to ask permission in a more formal, traditional, or especially polite way. Use can I in everyday English, where it often functions naturally as a request for permission even though it originally relates more directly to ability. The short’s own description highlights this exact contrast: ability versus asking for permission.

✅ May I leave early today?

Here, may I sounds more formal and classically polite.

✅ Can I leave early today?

In real conversation, this is very common and usually sounds natural.

✅ Can I lift this box by myself?

Here, can I is really about ability, not permission.

✅ Can I have your sandwich?
This sounds like a normal everyday request. In conversation, most speakers would choose can I here rather than the more formal may I.

The most common mistake is thinking can I is always wrong when asking permission.

In strict school-style grammar lessons, learners are often taught:

That distinction is useful, but in real everyday English, can I is extremely common for permission too. The difference is often more about tone and formality than about absolute correctness. The video’s own description frames the distinction in exactly those terms: ability versus asking for permission.

Another common mistake is using may I in very casual situations where it can sound overly formal or stiff.

Use this simple rule:

A practical shortcut:

Or even shorter:

may I = polished
can I = everyday