Have you ever wondered how to talk about possibility, obligation, or ability in English? If so, welcome to the world of modal verbs! Modal verbs are incredibly versatile and essential for expressing various tones, moods, and attitudes in English. In this guide, we will explore what modal verbs are, delve into their usage, and examine some common rules and examples.

Table of Contents

What Are Modal Verbs?

Modal verbs are auxiliary, or “helping,” verbs that modify the main verb in a sentence to express possibility, ability, necessity, or other conditions. These include words like “can,” “could,” “will,” “would,” “shall,” “should,” “may,” “might,” and “must.”


  • He can swim.
    • This shows ability.
  • You should study for the test.
    • This is a suggestion.

Additional Examples:


  1. Can: She can play the piano well.
  2. Could: When she was younger, she could climb trees easily.

Possibility and Speculation

  1. May: It may rain tomorrow.
  2. Might: I might visit my grandparents this weekend.


  1. Can: Can I use your phone?
  2. May: May I come in?

Obligation and Necessity

  1. Must: You must report to the office immediately.
  2. Have to: I have to pick up my kids from school.


  1. Cannot/Can’t: You can’t park here.
  2. Mustn’t: You mustn’t smoke in this area.

Offers and Invitations

  1. Will: Will you have some coffee?
  2. Would: Would you like to join us for dinner?


  1. Shall: Shall we go for a walk?
  2. Should: We should take a break.


  1. Could: Could you please pass the salt?
  2. Would: Would you mind helping me with this?

Future Probability

  1. Will: She will probably come to the party.
  2. Shall: They shall succeed with enough effort.

Past Probability

  1. Would have: She would have succeeded if she had tried.
  2. Could have: He could have won the race but decided to stop and help an injured runner
a list of modal verbs

These examples showcase the various contexts and conditions in which modal verbs are often used. They allow for a nuanced expression of mood, probability, ability, necessity, and more. By understanding how to use them appropriately, you can convey your ideas and attitudes much more clearly and effectively. Remember that accuracy is very important!

Types of Modal Verbs


  • Can: Can you finish the project by tomorrow?
  • Might: He might come to the party later.


  • Can: Maria can speak four languages.
  • Could: I could run fast when I was young.


  • Must: We must complete the assignment.
  • Have to: They have to take the medicine.

Request and Offers

  • Will: Will you marry me?
  • Would: Would you like some tea?

Additional Examples:


  1. May: You may find the book interesting.
  2. Could: They could arrive late due to traffic.


  1. Will be able to: She will be able to finish the project by next week.
  2. Would be able to: If she had more time, she would be able to complete it sooner.


  1. Should: You should take an umbrella; it looks like it’ll rain.
  2. Ought to: They ought to apologise for their behaviour.

Request and Offers

  1. Can: Can you help me with my homework?
  2. Shall: Shall I open the window for you?

These additional examples should provide a broader understanding of the different ways modal verbs can be employed for various purposes. Whether you’re indicating possibility, showing ability, emphasising necessity, or making requests and offers, modal verbs are your go-to tool for nuanced communication.

Rules for Using Modal Verbs

  1. No Conjugation: Modal verbs do not change form based on the subject.


  • Incorrect: She cans swim.
  • Correct: She can swim.

Additional Examples:

  • Incorrect: He wills go to the market.
  • Correct: He will go to the market.
  • Incorrect: They musts complete the project by tomorrow.
  • Correct: They must complete the project by tomorrow.
  • Incorrect: She coulds read when she was four.
  • Correct: She could read when she was four.
  • Incorrect: We cans see the mountains from here.
  • Correct: We can see the mountains from here.

As you can see, the modal verb stays the same form irrespective of the subject, thus making it simpler than regular verbs, which often require conjugation based on the subject. (Learn more in this article on subject-verb agreement.) Understanding this rule is essential as it simplifies the process of constructing sentences.

  1. Double Modals Are Rare: Using two modal verbs together is generally avoided.


  • Incorrect: She might can go.
  • Correct: She might be able to go.

Additional Examples:

  • Incorrect: They should must complete the project.
  • Correct: They should complete the project. / They must complete the project.
  • Incorrect: He will can join us later.
  • Correct: He will be able to join us later.
  • Incorrect: She may should attend the meeting.
  • Correct: She may need to attend the meeting. / She should attend the meeting.
  • Incorrect: We could will win the game.
  • Correct: We could win the game. / We will probably win the game.
  • Incorrect: I would can help you with that.
  • Correct: I would be able to help you with that.

By avoiding double modals, the sentences remain clearer and easier to understand. If you feel the need to use two modal-like ideas, consider replacing one with an equivalent phrase, like “be able to,” “have to,” or “need to,” among others. This will help you maintain the clarity and grammatical integrity of your sentences.

  1. Always Use Base Form: Always use the base form of the main verb after a modal.


  • Incorrect: He must to go.
  • Correct: He must go.

Additional Examples:

  • Incorrect: She can runs fast.
  • Correct: She can run fast.
  • Incorrect: They should eats healthily.
  • Correct: They should eat healthily.
  • Incorrect: We will sees you tomorrow.
  • Correct: We will see you tomorrow.
  • Incorrect: He might goes there.
  • Correct: He might go there.
  • Incorrect: She would likes some coffee.
  • Correct: She would like some coffee.

As shown, the main verb that follows a modal should always be in its base form. This is crucial for constructing grammatically correct sentences. Ensuring you follow this rule will make your English sound more natural and accurate. It will also help you to get a better score for Grammatical Range and Accuracy.

Common Mistakes

Confusing “Should” and “Must”

  • Should: Indicates advice or recommendation.
    • You should eat more fruits.
  • Must: Indicates a stronger necessity or obligation.
    • You must obey the law.

“Should” for Advice or Recommendation

  • You should exercise regularly for good health.
    • Here, “should” offers a suggestion for maintaining good health.
  • She should call her parents more often.
    • In this example, “should” advises more frequent contact with parents.
  • They should consider a different strategy.
    • “Should” here recommends contemplating alternative approaches.
  • We should invest in renewable energy.
    • This is a suggestion aimed at a better environmental future.

“Must” for Stronger Necessity or Obligation

  1. You must submit the application by Friday.
    • “Must” indicates a firm deadline that is non-negotiable.
  2. He must take his medication every morning.
    • Here, “must” emphasises the crucial nature of taking medication for health.
  3. They must arrive on time for the meeting.
    • The necessity of being punctual for the meeting is stressed by using “must.”
  4. We must reduce our carbon footprint.
    • This statement indicates an urgent need to act for environmental reasons.

As you can see, “should” is less forceful and is generally used for giving advice or making recommendations. In contrast, “must” implies a stronger sense of obligation or necessity. Choosing the appropriate modal verb can greatly influence the tone and meaning of your sentences.

Confusing “would” and “could”

These two modals are often confused by English learners. This is understandable because they can have slightly similar meanings. Both can be used in polite requests and both can appear in conditionals.

However, the main difference is that “could” shows possibility and “would” shows intention. For example:

  • If I had a million dollars, I would buy a big house.
    • This shows the intention to do something.  
  • If I had a million dollars, I could buy a big house.
    • This shows the possibility of being able to do it.

Confusing “can” and “would

These two modals are often confused. Again, it comes down to their basic function: “can” shows the ability to do something. Meanwhile, “would” has a range of uses as we can see above.

Here’s a visual lesson that I made for my social media followers:

Misplacing the Modal Verb

Sometimes, beginners struggle with placing a modal verb in a sentence.


  • Incorrect: He swim can.
  • Correct: He can swim.

Additional Examples:

  • Incorrect: She drive should carefully.
  • Correct: She should drive carefully.
    • Here, “should” should be placed before the main verb “drive” to offer advice about driving.
  • Incorrect: They must go will to college.
  • Correct: They must go to college.
    • “Must” should directly precede the main verb “go” to express necessity.
  • Incorrect: You sing can well.
  • Correct: You can sing well.
    • The modal “can” should come before the main verb “sing” to indicate ability.
  • Incorrect: He soon will arrive.
  • Correct: He will soon arrive.
    • “Will” should be placed right before “arrive” to denote future action.
  • Incorrect: We may late be.
  • Correct: We may be late.
    • The modal “may” should directly precede the main verb “be” to express possibility.

As shown, misplacing the modal verb can cause confusion and make the sentence grammatically incorrect. Ensure that the modal verb is placed right before the main verb to maintain the intended meaning and grammatical structure of the sentence.

In summary, understanding modal verbs is essential for mastering the English language. By knowing how to use them correctly, you can express a range of ideas—from possibility to obligation—clearly and efficiently.

Remember, the key is practice. The more you use them, the more natural they will become.