Modal Verbs of Permission

Modal Verbs of Permission (Can, May, Could)

Modal verbs of permission are used to show whether an action is allowed, requested, or forbidden. In English, the most common modals for permission are can, may, and could — but they are not interchangeable in every situation. Understanding the differences is essential for everyday conversation, polite requests, formal writing and Cambridge exams (B2 First & C1 Advanced).

Can – informal and everyday permission

Can is the most common modal for permission in spoken English. It is natural, direct, and informal.

Present / Future permission

You can borrow my book if you need it.
Students can leave early today.
You can use my phone if yours is dead.

In modern English, can is perfectly acceptable for permission, even though older grammar books preferred may.

Past permission (general)

When talking about general permission in the past, could is often used.

When I was a child, I could stay up late at weekends.
At university, students could use the library until midnight.

This refers to general rules, not one specific event.

May – formal or official permission

May is more formal and polite.

It is commonly used in:

official announcements
written rules
professional or academic contexts

Present / Future permission

You may enter the examination room now.
May I ask you a question?
Students may not use mobile phones during the test.

In exams, may signals controlled, formal language.

Past permission

We do not normally use may in the past.

Instead, use was / were allowed to.

When we were younger, we were allowed to stay up late.
She was allowed to take an extra day off work.

Could – polite or tentative permission

Could is used to make polite, indirect requests.

It sounds more respectful than can.

Asking for permission (present / future)

Could I use your laptop for a moment?
Could we leave a bit earlier today?

Could is usually used for asking, not giving, permission.

Past permission (general)

Like could, this refers to general permission, not a single event.

When I was younger, I could visit my friends freely.
In those days, people could travel without visas.

Negatives and prohibition

Informal prohibition

You can’t park here.
You can’t enter this room.

Formal prohibition

You may not enter without permission.
Candidates may not leave the room early.

Alternative form: was / were allowed to

This is the safest option when talking about:

specific permission in the past
formal or written English
They were allowed to visit the restricted area.
She was allowed to retake the exam.

Quick comparison

Can → informal permission
May → formal permission
Could → polite request
Was / were allowed to → past permission (specific)

Final tip for learners

In Cambridge exams, accuracy matters more than variety.

Use can naturally in speaking
Use may in formal writing
Use could for polite requests
Use was / were allowed to for past permission

Choosing the right modal shows control, tone awareness, and grammatical range — exactly what examiners are looking for.