English grammar · Intermediate
English Modals
The modal verbs (can, could, may, might, must, shall, should, will, would) add a speaker's judgement to a verb: how possible, how necessary, how certain, or how polite. They share one grammar, no -s, no to, no do in questions, and a bare infinitive after them, which is what makes them a family.
What it is
A modal verb sits in front of a main verb and colours it with the speaker's attitude. She swims is a fact; she can swim is ability, she must swim is obligation, she might swim is possibility, she should swim is advice. Nine core modals cover all of that, plus the semi-modals have to, need to, ought to, and be able to that fill their gaps.
You must be tired (deduction). You must leave now (obligation). Same modal, two meanings: context decides.
How to spot it
A modal never changes form and never takes to after it. If you see he cans or she must to, a modal has been treated like an ordinary verb.
- He can drive. (no -s on the modal, bare infinitive after it)
- Can he drive? (the modal itself moves to make the question)
- He can't drive. (not attaches directly to the modal)
- He has to drive. (have to is a semi-modal: it does take -s and do)
Modals have no past participle or -ing form. To say the same thing in another tense, switch to the semi-modal: I had to leave, I have been able to swim since I was five.
Modals Quick Reference
What each modal most often means
| Modal | Main meanings | Example |
|---|---|---|
| can | ability, permission, request | Can you swim? Can I leave early? |
| could | past ability, polite request, possibility | I could swim at five. Could you help? It could rain. |
| may | permission (formal), possibility | May I come in? It may snow tonight. |
| might | weaker possibility, tentative suggestion | She might be late. You might try restarting it. |
| must | strong obligation, certain deduction | You must sign here. He must be exhausted. |
| should | advice, expectation | You should rest. They should arrive by six. |
| will | future, prediction, willingness | It will rain. I'll carry that. |
| would | hypothetical, past habit, polite request | I would go if I could. Would you mind? |
| shall | offers and suggestions (I/we), formal future | Shall we begin? |
All 2 modals lessons
The pages in this section are organised by meaning rather than by word, because one modal usually has several jobs and one job is usually shared by several modals. Ability (can, could, be able to), permission (can, may, could), obligation (must, have to, should), possibility and deduction in the present and the past (may, might, could, must have), and the two most-searched single modals, would and could, each get their own page, with modal verbs as the overview.
- Would: Would is a modal verb, the past and conditional form of will. It has no -s form and is followed by a bare infinitive (she would go, not she would to go). Its core meaning is distance from reality: an imagined result (I would help), a softened request (Would you mind?), a habit that belongs to the past (we would swim every day), or a future seen from a past moment (she said she would call).
- Modal Verbs: Modal verbs are a small set of auxiliary verbs (can, could, may, might, will, would, shall, should, must) that add a speaker's judgement to the main verb: how possible, necessary, permitted, or certain something is. They share one grammar: no -s in the third person, no to before the following verb, and no do in questions and negatives. Each modal carries several meanings, and the context decides which one is meant.
Modals FAQs
- What are the nine modal verbs in English?
- Can, could, may, might, must, shall, should, will, and would. Ought to, need, and dare behave like modals some of the time and are often called semi-modals, together with have to and be able to, which express modal meanings with ordinary verb grammar.
- Why don't modal verbs take -s or to?
- Historically they were a separate class of verb that never developed those endings, and the grammar has stayed frozen. Practically, the rule is simple: the modal never changes (she can, not she cans) and the next verb is a bare infinitive (she can swim, not she can to swim). The exception is ought to, which keeps its to.
- What is the difference between must and have to?
- Both express strong obligation, but must usually comes from the speaker (I must call my mother, I feel I should) while have to comes from outside (I have to wear a uniform, the rule says so). In the negative they split completely: mustn't means it is forbidden, don't have to means it is not necessary.
- How do I talk about the past with a modal?
- For deduction and possibility, add have plus a past participle: he must have left, she might have forgotten. For ability, use could or was able to: I could swim at five, I was able to finish in time. For obligation, switch to had to, because must has no past form.
- Is could the past of can?
- Sometimes. I could swim when I was five is genuinely past ability. But could also works as a polite present request (Could you pass the salt?) and as present or future possibility (It could rain later). Treat could as its own modal with several meanings rather than as simply can in the past.