Modal Verbs in English: Meanings, Examples and Mistakes

Modal verbs are helper verbs that change the meaning of the main verb: can, could, may, might, must, shall, should, will and would, plus ought to. They show ability, permission, advice, obligation and possibility. A modal is always followed by the base verb: "You should call", never "You should to call".

If you are preparing for CELPIP, modals deserve more attention than most grammar points. The test rates your tone in Speaking and Writing, and modals are the quickest way to control it.

What are modal verbs?

Modal verbs sit in front of a main verb and add an attitude to it. Compare "I go", "I can go", "I should go" and "I must go". The action is the same. What changes is whether you are able to, whether it is a good idea, or whether you have no choice.

Three rules make modals different from ordinary verbs:

1. No "to" after them. "I can swim", not "I can to swim". The one exception is ought to.
2. No -s for he, she or it. "She can drive", not "She cans drive".
3. No "do" in questions and negatives. "Can you come?" and "I can't come", not "Do you can come?"

What is the full list of modal verbs?

English has nine core modal verbs: can, could, may, might, must, shall, should, will and would. Most grammar books add ought to as a tenth.

Then there are expressions that do a modal's job, often called semi-modals: have to, need to, be able to and had better. Most of them change form ("she has to", "they had to"), which a true modal never does. That is useful, because it lets you say things modals cannot, like "I will be able to help" or "We had to leave".

What does each modal verb mean?

Most modals do more than one job. Here are the main ones.

Notice that one modal can be soft in one sentence and firm in another. "You must sign in" is a rule. "She must be tired" is a guess you feel sure about. Context tells the listener which one you mean.

How strong is each modal?

For advice and obligation, modals sit on a scale from gentle to firm. Picking the right point on that scale is most of what sounding natural means.

The common mistake is using the firm end for everyday advice. "You must try this café" is fine as excitement between friends. "You must speak to your manager" said to a coworker who asked for help can sound like an order. "You should speak to your manager" or "It might be worth speaking to your manager" gives the same advice and keeps the relationship comfortable.

How do you use modal verbs to be polite?

Use could and would for requests, and might for suggestions. The further you move from can and must, the softer you sound.

For requests, here is the ladder from casual to very polite:

• "Can you send me the file?" Fine with a friend or close coworker.
• "Could you send me the file?" Polite, safe almost everywhere.
• "Would you mind sending me the file?" More polite. Note the -ing after "mind".
• "I was wondering if you could send me the file." Very polite, good for a request that is a real favour.

For suggestions and complaints, modals let you be clear without sounding rude:

• "You might want to check the schedule again" sounds helpful. "Check the schedule again" sounds annoyed.
• "Could you please look into this?" asks for action without blaming anyone.
• "I would appreciate it if you could reply by Friday" sets a deadline politely.

If you want more phrases like these, the free softening language lesson and the polite requests lesson in our vocabulary course have dozens, grouped by situation.

What are past modals?

Past modals are a modal plus have plus the past participle: should have gone, could have called, must have forgotten. You use them to look back at something that already happened, usually to talk about regret, missed chances or guesses.

In speech these get shortened to should've, could've and must've. That is where the common spelling mistake "could of" comes from. In writing, use "could have" or "could've", never "could of".

What are the most common modal verb mistakes?

Almost every modal mistake comes from treating a modal like a normal verb, or from picking the wrong strength. These are the ones I correct most often:

The mustn't and don't have to pair causes real confusion, because in positive sentences must and have to mean almost the same thing. In the negative they split completely. "You mustn't park here" means you will get a ticket. "You don't have to park here" means there are other options.

How do modal verbs help on the CELPIP test?

CELPIP does not score modal verbs as a separate item. What it does rate is tone. Speaking and Writing are each rated in four areas, and one of them, Task Fulfillment, includes tone. Grammar is rated too, inside Listenability in Speaking and Readability in Writing. In my experience, modals are the tool that fixes tone fastest, because changing one word moves a sentence from rude to polite. (How CELPIP scores grammar explains where grammar sits in each area.)

Three tasks show it clearly.

Speaking Task 1, Giving Advice. Imagine a friend is buying a used car and asks what to do.

• Too strong: "You must buy a newer car. You have to check everything."
• Better: "If I were you, I would ask for the service history first. You might also want to get a mechanic to look at it, and you should decide on a budget before you visit any seller."

The second answer gives three clear pieces of advice, and each one sounds like a friend talking. The Speaking Task 1 giving advice template shows how to build a full answer around that kind of language.

Speaking Task 6, Dealing with a Difficult Situation. These tasks often ask you to say no to someone or ask for a change. Soft modals carry the bad news without sounding cold: "I'm afraid I won't be able to cover your shift on Saturday. Would it help if I covered your Sunday shift instead?" The Speaking Task 6 template walks through how to structure the whole answer.

Writing Task 1, an email. Imagine writing to your building manager about a broken washing machine.

• Too strong: "You must fix the washing machine immediately."
• Better: "Could you please arrange a repair this week? I would be grateful for an update once a date is set."

Both say the same thing. Only one sounds like it came from a tenant the manager wants to help. The Writing Task 1 email template shows where requests like this go in each paragraph.

Practise your tone out loud: record a Speaking Task 1 answer in our AI-scored Speaking practice and see how it is rated. Your first practice set in each Speaking task is free once you sign up.

Can you choose the right modal verb?

Pick the better option for each sentence. Answers are below.

1. You ___ show your ID at the front desk. They won't let you in without it. (must / might)
2. ___ you help me carry this box upstairs? (Could / Must)
3. You ___ bring food tonight. We ordered plenty. (mustn't / don't have to)
4. I ___ have studied more before the test. (should / must)
5. All the lights are off. They ___ have gone out. (must / should)
6. If you have time, you ___ want to visit the farmers' market. (might / must)

Answers:

1. must (a rule).

2. Could (a polite request).

3. don't have to (not necessary).

4. should (regret).

5. must (a confident guess).

6. might (a gentle suggestion).