Permission: Can, Could & May

In English, three modal verbs — can, could, and may — are the main modals of permission, but they sit on one formality scale: can is informal and everyday, could is polite, and may is formal. Mastering permission means learning to pick the right modal for the right situation. Beyond these three, be allowed to fills the tense gaps that modals cannot reach — past, future, present perfect, and more. By the end of this lesson, you will also be able to tell the difference between permission, obligation, and prohibition.

Note: "Can" and "could" are also used for ability (see Ability: Can, Could & Be Able To). In this lesson, we focus only on their permission meaning. Context — especially who has authority and what rules apply — tells you whether a sentence is about permission or ability.

Asking & Giving Permission with Can

Can is the most common and natural way to ask for and give permission in everyday English. Even at A2 level, this is one of the first modal verbs you will master. You will hear it between friends, family members, classmates, and in casual workplaces.

Asking for Permission: Can I...?

• Can I borrow your pen?
• Can we leave early today, Ms Johnson?
• Can I open the window? It's very hot in here.

Giving Permission: You can...

• You can use my laptop if you need to.
• You can sit wherever you like.
• Sure, you can borrow my bike — just be careful.

Refusing Permission: You can't...

• Students can't eat or drink in the library.
• I'm sorry, but you can't park here. It's a no-parking zone.
• Visitors can't enter without a security pass.

Short Answers

Key point: Like all modal verbs, can never changes form — no -s, no -ing, no -ed.

• ✅ She can go now.
• ❌ She cans go now.

Permission or Ability? Context Decides

"Can" is also used for ability — how do you tell the difference? Look at the context:

For more on "can" and "could" for ability, see Ability: Can, Could & Be Able To.

👉 Practice Can & Can't for Permission →

Polite Permission: Could & May

When you need to be more polite or formal than "can", use could or may.

Could I...? — Polite Requests

Could is more polite and tentative than "can". Use it with people you don't know well, in professional settings, or when the request feels bigger:

• Could I have the bill, please?
• Could I speak to the manager?
• Could I trouble you for the salt?

Important: "Could" is mainly used for asking permission. It is not commonly used for giving permission — use "can" or "may" instead:

• ✅ Could I sit here? → Yes, of course you can.
• ❌ You could sit here. (This sounds like a suggestion, not permission.)

Don't confuse: "Could I...?" for a present polite request is NOT the past tense of "can". When someone says "Could I use your phone?", they mean right now — the past form makes the request more tentative and respectful, not past in time.

May I...? — Formal Requests

May is the most formal modal for permission. Use it in official, professional, and ceremonial situations:

• May I see your passport, sir?
• May I propose a toast?
• May I have your attention, please?

Don't confuse: "May" also expresses possibility ("It may rain tomorrow"). For permission, the key indicator is that someone in authority is involved, or you are making a polite request.

Giving Permission with May

People in authority — teachers, officials, managers — use may to give formal permission:

• You may leave the classroom now.
• Guests may use the swimming pool between 7 a.m. and 9 p.m.
• Visitors may enter free on Sundays.
• You may begin the exam.

Refusing Permission with May Not

May not is the formal way to refuse permission or state a prohibition:

• You may not take books out of this room.
• Passengers may not use electronic devices during takeoff.
• Readers may not remove reference books from the reading room.

Note: "May not" is never contracted to "mayn't" in modern English.

Responding to Permission Requests

Tip: Match the formality of your response to the request — a casual "Sure!" fits "Can I...?" while "Yes, you may" fits "May I...?".

👉 Practice Could & May: Polite Permission →

Formality Levels: Can vs Could vs May

The choice between can, could, and may depends on the situation and who you are talking to. This is the core skill of using modals of permission — matching the right level of formality to each situation. This B1-level challenge is what separates natural English from textbook English.

The Formality Scale

How to Choose: Match the Situation

Giving Permission: Formality Also Matters

Refusing Permission: Formality Also Matters

👉 Practice Choosing the Right Modal →

Be Allowed To & Past Permission

Can, could, and may are modal verbs — they only have one or two forms. When you need to express permission in other tenses, including past permission, use be allowed to:

Be Allowed To: All Tenses

Why do we need "be allowed to"? Because modal verbs cannot combine with other modals or auxiliaries:

• ❌ I will can come. → ✅ I will be allowed to come.
• ❌ She has could leave. → ✅ She has been allowed to leave.

This is the same reason why be able to fills the gaps for ability (see Ability: Can, Could & Be Able To).

Past Permission: The "Could" Trap ⚠️

This is one of the most tested rules in English permission grammar — and one of the easiest to get wrong.

✅ General / Habitual Past Permission → "could" is OK

When permission was a regular, repeated thing over a period of time, you can use "could":

• When I was a child, I could play outside until dark. ✅
• At university, I could borrow up to ten books. ✅
• When he worked abroad, he could take extra holiday each year. ✅

❌ Specific One-Time Past Permission → Use "was/were allowed to"

When someone gave permission for a specific occasion, do NOT use "could" — use "was/were allowed to":

• He was allowed to leave work early last Tuesday. ✅
• He could leave work early last Tuesday. ❌ (sounds like ability, not permission)
• After the exam, we were allowed to leave the hall. ✅
• After the exam, we could leave the hall. ❌
• I finally was allowed to see the confidential report after I got security clearance. ✅

Why does this happen? Because "could" in past contexts sounds like general ability or capacity, not a one-time granted permission. Listeners will interpret "He could leave early" as "He had the ability to leave early", not "Someone gave him permission to leave early."

✅ Negative Past Permission → Both work

In the negative, both forms are acceptable for any type of past permission:

• I couldn't go to the party. ✅
• I wasn't allowed to go to the party. ✅
• She couldn't stay out past 10 p.m. ✅
• She wasn't allowed to stay out past 10 p.m. ✅

Summary Table

Parallel with ability: This rule mirrors the ability distinction — you also cannot use "could" for a specific past achievement, only "was/were able to". See Ability: Can, Could & Be Able To for comparison.

👉 Practice Be Allowed To & Past Permission →

Permission vs Obligation vs Prohibition

At B2 level and above, you need to distinguish three different functions of modal verbs: permission, obligation, and prohibition. This is not just about asking for permission anymore — it is about understanding what modals do in a sentence.

The Three Functions (Plus "No Obligation")

The Critical Distinction: Mustn't vs Don't Have To ⚠️

This is one of the most common and dangerous mistakes at B2 level — getting it wrong can completely change the meaning of your sentence:

Compare:

• ⚠️ "You mustn't attend the meeting." = You are forbidden from attending!
• ✅ "You don't have to attend the meeting." = Attendance is optional.

These two sentences have opposite meanings. Confusing them can cause serious misunderstandings.

Quick Decision Guide

When you see a sentence about rules, requirements, or choices, ask yourself:

Examples in Context

• Employees must wear a uniform. (Obligation — it's compulsory.)
• You can use this coupon until the end of the month. (Permission — it's allowed.)
• You mustn't touch the paintings in the gallery. (Prohibition — it's forbidden.)
• Students may bring a dictionary to the exam if they want to. (Permission — it's optional.)
• You don't have to pay in cash — card is also fine. (No obligation — it's your choice.)
• All passengers must fasten their seatbelts during landing. (Obligation — safety requirement.)
• You can't enter the exam room after the test has started. (Prohibition — not permitted.)

👉 Practice Permission vs Obligation vs Prohibition →

Common Mistakes to Avoid

Quick Summary

The Permission Formality Scale

Quick Decision Guide: Choosing Your Modal

1. What function? Permission → can/may | Obligation → must/have to | Prohibition → mustn't/can't | No obligation → don't have to
2. What formality? Casual → can | Polite → could | Formal → may
3. What tense? Present/past → modals work | Future/perfect/after other verbs → use be allowed to
4. Past permission — general or specific? General/habitual → could is OK | Specific one-time → was/were allowed to only

Practice Tips

1. Formality check: Before speaking, ask yourself — is this situation casual (→ can), polite (→ could), or formal (→ may)? Matching the right modal to the right situation is the most important skill in this topic.
2. Permission diary: Write down five things you are allowed to do at work or school and five things you are not allowed to do, using both "can/can't" and "be allowed to".
3. Past permission stories: Describe rules from your childhood — what could you do? What weren't you allowed to do? Practise the "could vs was allowed to" distinction for specific events.
4. Watch for the trap: When talking about a specific past event, always choose "was/were allowed to" over "could" for permission.
5. Modal function quiz: When you read signs and rules in English, decide: is each one about permission, obligation, or prohibition?

Practice All Exercises

Ready to practise everything you have learned? These modal verbs exercises cover can, could, and may for permission — from A2 basics to B2 mixed modals. Start with Set 1 for basics, or jump to Set 5 for the advanced challenge:

Now try the exercises to practise what you've learned!