Should I say 'Can I' or 'May I'?

'Can I' is fine in everyday casual situations: 'Can I borrow a pen?'. 'May I' is more formal and polite, suitable for professional contexts or speaking to strangers: 'May I come in?'. Some teachers consider 'May I' more correct, but 'Can I' is universally accepted in modern English.

Is 'Could I' more polite than 'Can I'?

Yes. 'Could I' adds politeness by sounding less direct: 'Could I borrow your phone?' is gentler than 'Can I borrow your phone?'. Use 'Could I' for polite requests, especially with people you don't know well. Despite the past form, 'could' here is about politeness, not time.

What's the difference between 'mustn't' and 'may not'?

'Mustn't' is a strong prohibition: 'You mustn't tell anyone'. 'May not' is a formal denial of permission, often in rules: 'Students may not use phones in class'. Both refuse permission, but 'mustn't' is stronger and more personal; 'may not' sounds institutional.

Can I use 'can' to give permission?

Yes: 'You can leave early today', 'You can use my car'. This is the everyday way to grant permission. For more formal permission, use 'may': 'You may now begin the test'. Both work; choose based on the formality of the situation.

Why is 'Can I to go' wrong?

'Can' is a modal verb and is always followed by the base form of the verb — never 'to'. Say 'Can I go?'. The same rule applies to 'may', 'could', 'should', 'must', and other modals. Drop the 'to' whenever you use a modal verb.

Modal Verbs of Permission (can/may)

Asking for and giving permission with can/may

Last updated 13 June 2026

beginner

Use 'can' and 'may' to ask for and give permission. 'Can' is informal and common in everyday speech; 'may' is more formal and polite. Both are modal verbs, so they're followed by the base form of the verb without 'to'.

When to Use Modal Verbs of Permission (can/may)

•Asking permission: Can/May I open the window?
•Giving permission: You can leave early.
•Formal permission: May I speak to the manager?
•Rules/allowance: Students may not use phones in class.
•Polite offers: Can I help you?

How to Form Modal Verbs of Permission (can/may)

Affirmative (+)

Subject + can/may + base verb

Negative (-)

Subject + cannot/can't / may not + base verb

Question (?)

Can/May + subject + base verb?

💡 May is more formal than can. Use cannot/can't for prohibition; may not is formal/uncertain permission.

Examples of Modal Verbs of Permission (can/may)

✓Can I borrow your pen?

✗Can I to borrow your pen?

No 'to' after modals.

✓You can sit here.

✗You can to sit here.

Base verb after modal.

✓May I come in?

✗May I to come in?

Use base verb after may.

Common Mistakes with Modal Verbs of Permission (can/may)

💡 Practice Tips for Modal Verbs of Permission (can/may)

• Use may for formal situations; can for casual everyday permission.
• No 'to' after modal verbs.
• Cannot/can't = prohibition; may not = formal/uncertain permission.
• For ability, use can; for permission, context matters.

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When to Use Modal Verbs of Permission (can/may)

How to Form Modal Verbs of Permission (can/may)

Examples of Modal Verbs of Permission (can/may)

Common Mistakes with Modal Verbs of Permission (can/may)

✗Can I to go now?

✗May not you enter?

✗You may to leave.

💡 Practice Tips for Modal Verbs of Permission (can/may)

Frequently Asked Questions about Modal Verbs of Permission (can/may)

Should I say 'Can I' or 'May I'?

Is 'Could I' more polite than 'Can I'?

What's the difference between 'mustn't' and 'may not'?

Can I use 'can' to give permission?

Why is 'Can I to go' wrong?

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