Must vs. Have To

'Must' and 'have to' express different levels of obligations. In this lesson, we will learn more about them and when to use each of them.

What Is Their Main Difference?

The main difference between 'must' and 'have to' is that 'must' is a modal verb and 'have to' is a semi-modal verb.

'Must' is a modal verb (also known as modals). Modals give additional information about the main verb of the sentence. 'Must' expresses necessities, likely events, and suggestions. Have a look:

You must join the book club.

She must be insane.

'Have to' is a semi-modal verb (also known as semi-modals). Semi-modals function similarly to modals. They sometimes act like modals and sometimes act like a main verb. It is used to express necessities, obligations, certainty, etc. For instance:

I have to call an ambulance.

She has to be at work early in the morning.

Similarities

Talking about Obligations

Obligations are things that are needed to be done. We use 'have to' and 'must' to express such actions and events. There is a distinction that requires attention:

'Must' is used for obligations and needs that are external. By external, we mean that they have been motivated and assigned by someone else. Not fulfilling such actions may also lead to punishment or penalty. 'Must' is more formal and more common than 'have to' in this context. For example:

You must finish your homework.

You have to finish your homework.

'Have to' is used for obligations and needs that are motivated and assigned by oneself. There may be no punishment and penalty if the action or event is not fulfilled. 'Have to' is more common that 'must' in this context. For instance:

I have to be home soon.

I must be home soon.

Negative Forms

The negative form of 'must,' 'must not,' expresses absolute obligation:

You must not eat sweets.

Students must not enter the 7th floor.

The negative form of 'have to,' 'don't have to,' is used to say that fulfilling something is not absolute and it is more of a suggestion:

You don't have to eat sweets.

Students don't have to enter the 7th floor.

With Tenses

'Must' and 'have to' are used in the past, present, and future tense.

Must

'Must' can refer to all three tenses with the help of adverbs of time such as 'earlier,' 'right now,' 'next week,' etc. Watch:

You must have joined us earlier. → Past

You must join us right now. → Present

You must join us next week. → Future

Have to

'Have to' can also refer to all three tenses by changing taking one of the forms 'had to,' 'have/has to,' or 'will have to.' Have a look:

You had to call the police. → Past

You have to call the police. → Present

You will have to call the police. → Future

Comments

(0)

Share on :