Modal Verbs: What Are Modal Verbs? Definition and Examples

By Carly Forsaith, updated on April 28, 2023

If you want to learn more about modal verbs, you've come to the right place. This article will cover everything you need to know about modal verbs, what they're for, and how to use them.

In short, though, modal verbs are a kind of auxiliary verb that you can use alongside a main verb to discuss a hypothetical situation. They indicate things like possibility, likelihood, permission, and so on.

This guide is part of our free online Grammar Book.

What Are Modal Verbs?

Modal verbs are a kind of auxiliary verbs. Auxiliary verbs are also known as helping verbs, which says a lot about their role in English grammar. First, they're always used alongside a main verb and rarely alone because their primary function is to help the main verb. 

What do they help the main verb do, I hear you ask? Well, a bunch of stuff. Their primary role is to indicate that the discussed situation is hypothetical and hasn't happened yet. They tell you how likely it is that it'll happen, the necessity of it happening, or whether there's permission necessary for it to happen, for instance. Don't worry; we'll go into more depth about all this in the following sections.

In other words, you might say that modal verbs change the meaning of the main verb slightly. Take the following two sentences, for example:

I walk to work nowadays.

I can walk to work nowadays.

See how the modal verb 'can' changes the meaning of the verb 'walk.' The first sentence is a general statement that shows the person does walk to work. The second sentence doesn't imply that the person actually walks to walk. It just says that they can if they want to. Maybe they had an accident that prevented them from walking for a while. But now they can. Or perhaps the weather hasn't been nice enough for them to walk, but now it is. Whatever it is, the second sentence is the one that indicates the possibility.

Note that modal verbs can be used to talk about past, present or future actions. We'll get into all that a bit later.

Here's a list of the most common modal verbs alongside the functions they can carry out:

  • can - permission, possibility, request
  • may - possibility, permission, request, likelihood
  • might - possibility, likelihood
  • could - a past form of 'can,' possibility, request
  • should - suggestion, likelihood
  • would - a past form of 'will,' request
  • will - talk about future action, request
  • must - obligation, likelihood

How to Make Sentences with Modal Verbs

There are a few things you need to know to make a grammatically correct sentence using a modal verb.

First, a modal verb is always directly followed by a main verb. Second, the main verb is always in the infinitive form. Check it out:

You could study online.

If you want to ask a question, the formula is slightly different. The modal verb comes first in the sentence, followed by the subject, then the main verb.

Could you study online?

When Are Modal Verbs Used?

As we've just learned, modal verbs indicate possibility, ability, likelihood, or permission, allowing you to make a request or a suggestion or to express obligation.

But how does that work? To show you, I will take you through each of these one by one, with examples.

To Indicate Possibility

As we saw earlier, the most common modal verbs that express possibility are:

  • can
  • may
  • might
  • could

So let's take a look at an example of each:

I can read really fast.

We may go on holday in April.

They might not want to join us.

You could take a nap if you're tired.

To Indicate Likelihood

The best modal verbs for expressing likelihood are:

  • may
  • might
  • should
  • must

Here's an example sentence for each:

She may be up to it if we make it worth her while.

You might see the Northern Lights if you to Norway.

You should start to feel better thirty minutes after you've taken this pill.

The building is derelict; it must be getting demolished soon.

To Indicate Permission

To discuss permission, use one of the following verbs:

  • can
  • may

You can invite your friend for a sleepover if you'd like.

You may leave the table if you're finished.

To Make a Request

The commonly used modal verbs for making a request are:

  • can
  • may
  • would
  • could
  • will

Can I borrow some money from you?

May we join you?

Would you like some more coffee?

Could you turn the volume down please?

Will you let us in.

To Make a Suggestion

To make a suggestion, the best modal verb to use is 'should.' Here are a few examples of what that would like in a sentence:

You should take a nap if you're not feeling great.

Maybe we should try a marrage counsellor.

If he likes to play soccer he should join a team.

To Express Obligation

'Must' is the only verb that expresses obligation. Here are a few example sentences that use this verb.

This is delicious! You must share your recipe with me.

We must go home now; our curfew is at 5pm.

I must try the lobster; I've heard it's great.

Using Modal Verbs with Other Tenses

Did you know that you don't have to use modal verbs in just the present indefinite tense in all the above scenarios? You can also use them in the other present tenses, as well as some past and future tenses. Let's take a look.

Present Continuous

You can use modal verbs in the present continuous tense to talk about an event that could or should be taking place in the current moment or an event that may occur in the future. For example:

You should be doing your homework!

I don't know if I can make it on Friday; I might be working

I heard you caught COVID. You must be feeling awful.

The formula is [modal verb] + be + [present participle].

Top Tip! The present participle is the verb in its ing form.

Present Perfect

Modal verbs combined with the present perfect tense allow you to talk about hypothetical events that would have started in the past and continued into the present.

They could have arrived by now if only they'd left on time.

You should have warned me sooner.

We would have bought four coffees if we'd known you were coming. 

The formula is [modal verb] + have + [past participle].

Present Perfect Continuous

Modal verbs with the present perfect continuous tense help you talk about a hypothetical event that would have started in the past and, if they had, would be continuing right now. 

She may have been waiting for the right time to tell you.

Why did you say it so loudly? Somebody could have been listening.

I would have been sleeping if it weren't for the crying baby.

The formula is [modal verb] + have been + [present participle].

Past Indefinite

Talk about the possibility of things you used to be able to do with the past indefinite - also known as the past simple.

Only 'could' and 'would' can be used with the past tenses, as they are past tenses of 'can' and 'will.'

Tommy could run further than me back then. How things have changed!

On Friday nights we would make margaritas after work; it was our tradition.

The formula is could/would + [infinitive].

Top Tip! With the past indefinite, notice how we're talking about events that actually happened, as opposed to all the other tenses which are used to talk about hypothetical situations.


The modal verb 'will' is already the standard verb for forming future tenses, so do that to be safe. If you want to be adventurous, use any modal verb with the future tense.

Modal verbs with future tenses will allow you to talk about... you guessed it, future events.

I will sit at the head of the table.

He should set sail tomorrow.

We must bring her a gift when we visit her tomorrow.

The formula is [modal verb] + [infinitive].

Other Uses of Modal Verbs

We've covered quite a bit already about the different functions of a modal verb. But what if I told you there's, even more, they can do? That's right; while a modal verb's primary function is to express possibility, likelihood, and all the other scenarios we learned above, they can also help with a few other things.

To Form the Future Tense

There's one specific modal verb you can use to form the future tense, and that's 'will.' As you may already know, the future tense in English grammar is created like this:

will + [infinitive]

So this is what it will look like in a sentence:

Tom and I will bring wine.

To Inform Verb Mood

Some modal verbs can be used to indicate mood. The interrogative, conditional, and subjunctive moods, specifically. Those modal verbs are:

  • would
  • could
  • should

Let's have a look at some examples:

Would you pass me the salt? (interrogative)

You could sell your house and make a profit. (subjunctive)

If you want to pass your exam you should start studying. (conditional)

A Note on Negative Modal Verbs

What if you're making a negative statement that contains a modal verb? Then how should you proceed? That's easy enough! All you need to do is use the modal verb that you would have used anyways and add 'not' or the contraction 't' immediately after.

Here's an example of a positive statement containing a modal verb and its negative equivalent.

You should waste food.

You shouldn't waste food.
You should not waste food.

Concluding Thoughts on Modal Verbs

That pretty much concludes today's article on modal verbs. I hope you found it helpful! Let's summarize what we've learned:

  • A modal verb's primary use is to express permission, possibility, likelihood, or obligation or make a request or suggestion.
  • The future tense is formed with the modal verb 'will.'
  • Modal verbs also help us form the interrogative, conditional, and subjunctive moods.
  • To use a modal verb in a negative statement, just add 'not' or ''t.'

If you enjoyed this article and want to continue your grammar education, check out our Grammar Book. It's a free online database full of articles on different grammatical concepts. Enjoy!

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Written By:
Carly Forsaith
Carly Forsaith is one of the lead freelance writers for Carly is a copywriter who has been writing about the English language for over 3 years. Before that, she was a teacher in Thailand, helping people learn English as a second language. She is a total grammar nerd and spends her time spotting language errors on signs and on the internet.

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