Modal verbs are small but powerful words that cause many English learners stress and confusion. Don’t worry—this guide will make them clear and simple for you.

There are 9 core modal verbs in English:

can, could, may, might, must, shall, should, will, would

We’ll look at their forms, functions, and lots of examples to help you master them.

1. The Form of Modal Verbs

The good news: modal verbs are simple!

• They have one form only.
  • No -ing (never “musting”).
  • No -ed (never “musted”).
  • No -s in third person (never “shoulds”).
• They are followed by a base verb (not “to + verb”).
  •  I might bake a cake later. Right
  •  I might to bake a cake. Wrong
• Questions: invert subject + modal (Can I help you?).
• Negatives: add not (should not, could not).
  • Cannot = one word.
  • Contractions are common (can’t, won’t), except mayn’t (rare).

2. Can

• Present ability: I can speak Spanish.
• Lack of ability: I can’t drive.
• Permission: Can I have pizza for breakfast? → No, you can’t.
• Requests: Can you help me?
• General possibility: It can be cold in March.
• Deductions (impossibility): That can’t be true.

3. Could

• Past ability: I could see better when I was younger.
• Polite requests: Could you help me with this?
• Possibility: It could rain later.
• Past deductions: She could have missed the bus.

4. Might

• Polite requests (formal): Might I borrow your umbrella?
• Possibility: I might not go to Spain this summer.
• Past possibility: The cat might have eaten the fish.

5. May

• Formal permission: May I use the room?
• Giving permission: Yes, you may. / No, you may not.
• Possibility/deduction: She may be upset about the meeting.

6. Must

• Strong deduction (certainty): He must be tired after that trip.
• Obligation (internal or rules/laws):
  • I must call my dad—it’s his birthday.
  • You must wear a seatbelt.
• Prohibition: You mustn’t talk during the film.
• Strong recommendation: You must try this dessert!

7. Should

• Obligation / right or wrong: You should wear your seatbelt.
• Advice / suggestions: You look tired. You should rest.
• Expectations: The flight should be on time.

8. Shall

(Mostly British English, less common in American English.)

• Suggestions: Shall we go to the beach?
• Offers: Shall I help you?
• Asking for advice: What shall we do next?

9. Will

• Future statements: I’ll call you tomorrow.
• Promises: I won’t be late.
• Predictions: It will rain tomorrow.
• Requests: Will you pack the snacks, please?

10. Would

• Polite requests: Would you pass me the salt?
• Advice: If I were you, I’d talk to him.
• Hypothetical situations: What would you do if you won the lottery?
• Past of “will” in reported speech:
  • Direct: He said, “I’ll help you.”
  • Reported: He said he would help me.

Final Thoughts

Modal verbs are extremely useful for expressing ability, possibility, permission, obligation, and more. With practice, you’ll start using them naturally in both speaking and writing.