Modal Verbs Explained (KS2)

Modal verbs are one of those grammar terms that sounds far trickier than it really is. They are simply small helper words, like can, might and must, that tell us how possible or certain something is. This guide explains what a modal verb is, lists all nine of them, and shows how Year 6 children can use them with confidence.

What is a modal verb?

A modal verb is a special kind of helper verb that sits in front of another verb to change its meaning. On its own, the verb rain simply describes the weather. Add a modal verb and you change how likely it feels: it will rain, it might rain, it could rain. The main verb stays the same, but the level of certainty shifts each time.

Modal verbs help us show four main things:

• whether something is possible (it might snow)
• whether something is certain (she will win)
• whether something is allowed (you may leave)
• whether something is necessary (we must hurry)

Because they support another verb rather than standing alone, modal verbs belong to a group called auxiliary, or helping, verbs. If you would like a refresher on how verbs fit alongside nouns, adjectives and the rest, our guide to word classes at KS2 is a friendly place to start.

The full list of modal verbs

There are nine main modal verbs that children learn at KS2, and it is well worth learning them as a set. Here they are with a simple example of each.

That is the complete list: can, could, may, might, shall, should, will, would and must. A handy way to remember it is to notice that several of them come in pairs, such as can and could, shall and should, will and would.

How modal verbs change possibility and certainty

The clever thing about modal verbs is that swapping one for another changes how sure a sentence sounds, even when nothing else moves. Look at the same sentence three ways:

• It will rain this afternoon. (sounds certain)
• It might rain this afternoon. (sounds possible)
• It could rain this afternoon. (sounds uncertain)

You can line modal verbs up roughly from "very sure" to "not very sure". Must and will feel strong and certain. Should sits in the middle. Might, may and could feel more open and possible.

This is why understanding modal verbs and possibility matters for clear writing. If a Year 6 pupil writes the dragon will return, the reader feels sure it is coming back. Change it to the dragon might return and the reader is left wondering. The right modal verb gives a writer real control over the mood of a story or the strength of an argument.

Modal verbs and adverbs of possibility

Modal verbs are not the only way to show how likely something is. Some adverbs do a similar job, and these are called adverbs of possibility. Common ones include perhaps, possibly, probably, maybe and certainly.

Often you can express a similar idea either way:

• It might be late. (modal verb)
• Perhaps it is late. (adverb of possibility)

Both sentences soften how certain the writer sounds. Year 6 pupils are sometimes asked to spot the difference, so it helps to remember the simple test: a modal verb teams up with another verb (might be), while an adverb of possibility usually stands alone and can often be moved around the sentence (Perhaps it is late / It is, perhaps, late).

Why modal verbs are not the same as ordinary verbs

Modal verbs behave differently from ordinary verbs, and noticing this is the key to getting them right.

First, they do not change their spelling for he, she or it. With a normal verb we add an s: she runs, he plays. Modal verbs never do this. We say she can swim, never "she cans swim", and he must go, never "he musts go".

Second, they are followed by a plain verb with no "to". We say you should rest, not "you should to rest". Compare that with the ordinary verb want, which does need to: you want to rest.

So a modal verb is a helper that always works as a team with another verb, never takes an s, and never needs to afterwards.

How modal verbs appear in the Year 6 SPaG test

Modal verbs are part of the statutory grammar that children meet, usually in Year 5, and they can come up in the Key Stage 2 grammar, punctuation and spelling test in Year 6. Questions are short and focused. A pupil might be asked to:

• circle the modal verb in a sentence
• choose the modal verb that best completes a sentence
• explain or show how a modal verb changes how certain a sentence sounds

The questions test understanding rather than tricky vocabulary, so a child who can recognise the nine words and feel the difference between might and will is in a strong position. If you would like the bigger picture of how this fits the rest of the paper, our overview of what the SPaG test involves walks through it calmly.

Modal verbs also sit near another Year 6 topic, the subjunctive mood, where verbs talk about wishes and possibilities. The two ideas are separate, but both deal with things that are not quite certain, so meeting modal verbs first makes the subjunctive feel friendlier later.

Practice ideas: change how certain a sentence sounds

The best way to understand modal verbs is to play with them, and this needs nothing more than a scrap of paper. Try this together at home.

Start with a plain sentence, then rewrite it to change how sure it sounds:

• Start: The team wins the match.
• Certain: The team will win the match.
• Possible: The team might win the match.
• Necessary: The team must win the match.

Then turn it into a quick game. One person says a modal verb, such as should or could, and the other makes a sentence using it. You can keep it silly (A penguin could live in our bathtub) because laughing while learning helps it stick. To stretch a confident learner, ask them to add an adverb of possibility too: Perhaps the team will win.

How SATS LION helps

SATS LION turns tricky SPaG topics like modal verbs into short, friendly practice that feels more like a game than a test, all mapped to the Key Stage 2 curriculum. Children meet each idea in small steps and revisit it just as it is about to fade, so it settles in for good.

If you would like to see how it works, you can explore the features here.