Use of Must And Have to

Use of Must And Have to

Must and have to are both verbs in English, but they are used differently. We use must when talking ab0ut something certain and subjective, whereas have to is used to talk about obligation that is objective.

When to use must:

We use the modal verb must when we want to express personal obligations or express what the speaker think is necessary. Overall, the modal verb must is related to obligations that are subjective to us.

How to use the modal verb must:

Must is a modal auxiliary verb. It is always followed by the main verb, and this is how it structured:

Subject + must + main verb (without "to").

Let’s look at some examples:

Subject Auxiliary must Main verb Rest of the sentence
I Must Go Home
I Must Visit London.
I Must Stop Now.

As the examples shows the main verb is only the base verb without “to”.

🚫 Incorrect: I must to go home.


✅ Correct: I must go home.


When to use “have to”:

We often use have to express impersonal obligations, things that often related to others or on oneself. Therefore, have to is often objective rather than subjective.

As we can see from the examples, the obligation is not subjective rather the obligation is imposed from the outside, objective.

How to use “have to”:

It is worth to clarify that “have to” is not a modal verb in fact it is not even an auxiliary verb. It comes to serve as substitute for “must”, because it is enabling people to express the idea of obligation or duty.

The structure of “have to” is:

Subject + auxiliary + have + infinitive (with to).


Let’s see some examples:

Form Subject Auxiliary verb Main verb “Have” Infinitive (with to) Rest of the sentence
Affirmative She - has to work -
Negative I do not have to see the doctor
Question did you have to go to school


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