When to use must and have to. Modal verbs Must, Have to, Should, Ought to

What is the difference between must and have to English?

Here you can find out the difference between the modal verbs must and have to.

Modal verbs in English they are often similar in meaning. Their main function is to show how the speaker evaluates the action: whether it is possible or impossible, whether something should be done or not.

In order to show the obligatory nature of an action, the verbs must are usually used. and have to. For example:

I must leave now. - I need to leave right now.
I have to wear my uniform every day. - I have to wear my uniform every day.

As can be seen from the examples, must and have to have a similar meaning, but still carry different semantic connotations. It is believed that the word must gives an action increased obligation or necessity.

The difference is that the verb must is personal, that is, we ourselves decide what we must and what we do not. Meanwhile, the verb have to is more often used in situations where someone has laid down these laws for us. Let's look at one example:

I must see my dentist. - I need to go to my dentist.
I have to see my dentists twice a year. - I need to go to my dentist twice a year.

In the first example, the word must indicates an increased need and the fact that the person himself made this decision. In the second sentence, the modal verb have to indicates a slight degree of obligation and that the action was recommended to the person by someone else.

In general, must verbs and have to can be used interchangeably, especially when it is difficult to tell the difference. For example:

He must be at work at 7 am. = He has to be at work at 7 am. - He definitely (needs) to be at work at 7 am.

It’s another matter when must is used to express one’s opinion rather than an obligation. For example:

It's rather cold. It must (not ‘have to’) be snowing. - Quite cold. It must be snowing.

There is a noticeable difference between the negative forms of verbs: mustn’t - a strict order not to do something; don’t/doesn’t have to - there is no need to do something or is optional. Let's look at a few examples:

You mustn’t be late for this meeting. - You can't be late for this meeting.
They don't have to pay the fee. - They don't have to pay.

It is noteworthy that the verb must does not have a past or future tense form. In such cases, have to replaces it. For example:

He had to prepare the written report two days ago. - He should have prepared a written report two days ago.
You will have to study hard to achieve the results. -You need to study hard to achieve results

Must is a very “hard” verb that expresses the obligation or need to do something. Must stronger than should. If in case should there is still some choice (to do or not to do), then in the case must no choice! This is an order.

Have to has the same meaning as must.

1. Must and have to are used to express the need to do something.

Example

I must leave. - I have to leave.
I have to leave. - I have to leave.
In this situation must And have to are used interchangeably.

2. Difference in the use of must and have to

Must is more personal in nature. Must used to express personal feelings and sensations.

Example

I must do my best. - I have to do my best.
In this case, the speaker expresses his feelings about this matter.

Have to is impersonal in nature. Have to used when talking about facts rather than personal feelings.

Example

I have to visit my doctor. - I have to visit my doctor.
Apparently, not everything is in order with your health, and this is a fact that you cannot argue with, and not some kind of personal feeling.

Note

Sometimes the difference is in use must And have to so subtle that it is difficult to determine which verb to use. In such situations it is better to use have to.

3. Must - there is no past!

Remember, verb must has no past tense form!
Therefore, it can be used for the present and future tenses, but not for the past.

Example

We must visit a doctor now. - We must visit the doctor now.
We must visit a doctor tomorrow. - We have to visit the doctor tomorrow.

4. Have to - for all forms

Unlike must, have to can be used for all forms, including the past tense.

Example

I had to visit my doctor. - I had to visit my doctor.

We can't say here must, because time is past! Therefore, we calmly use the equivalent must - have to!

5. Logical inference

Must used when the speaker draws a conclusion based on available facts. And although he has full confidence that his conclusion is absolute truth, it's not far from that. The Russian analogue is the “should be” construction. And where it should be, there it is must!

Example

The ground is wet. It must be raining. - The ground is wet. It must be raining.

The ground is wet - so we concluded that it is raining! And since our logic is ironclad, we use must! After all, it's raining must go, he just can’t help but go!

6 Mustn’t and don’t have to are two big differences

Mustn't= don't do this! This is an order! (don't do it)
Don't have to= there is no need to do this or it is not necessary (but in principle it is possible)

Examples

You mustn’t be late. - You shouldn't be late.
(Don't be late! You can't be late!)

You don't have to be on time. - You don't have to be on time.
Those. you may be late. But in principle you can arrive on time.

Uses of the verb Must

To express urgent advice or command, both to oneself and to others.
To express the suggestion that something may be plausible or probable.

Features of the use of the verb Must

The construction must have + past participle is used to express an assumption that relates to the past.
Must is not used to express ought in the past tense. The verb used for this is had to.
Must be used in indirect speech to express a past action.

Examples

Must I finish this exercise now? – Should I finish this exercise now? (the need to perform an action)
It is almost 8 o"clock. You must hurry up - It’s almost 8 o’clock. You need to hurry up. (urgent advice or order)
This must be the right answer - This must be the correct answer. (expression of assumption)
I can't find my wallet. I must have left it at home - I can't find my wallet. I must have left his home. (an expression of an assumption that refers to the past)
I knew there must be some solution – I knew that it should have been some kind of solution. (used in indirect speech to express a past action)
You must not touch bare wires - You must not touch bare wires. (order)

#2 Modal verb Have to

Uses of the verb Have to

To express the need to perform an action.
To express the likelihood of something (more often used in American English).

Features of the use of the verb Have to

In interrogative and negative sentences used with the auxiliary verb do/does/did/will, etc.
Verb form changes depending on time.

Examples

You don"t have to make a decision right now - You don’t have to make a decision right now. (no need to take an action)
My sister is short-sighted. She has to wear glasses – My sister is nearsighted. She has to wear glasses. (necessity)
Do you have to go shopping today? We can do it tomorrow together – Do you need to go shopping today? We can do this tomorrow together. (necessity)
We are still on the way. It has to be further than we thought – We are still on the way. It must be further than we thought. (expression of assumption)
You had to turn left at the crossroads - You had to turn left at the crossroads. (not the speaker’s personal opinion, but a necessity due to certain circumstances)
You will have to send her an e-mail - You will have to send her an e-mail. (necessity)

#3 Modal verb Should

Uses of the verb Should

To express a need, advice, recommendation.

Features of the use of the verb Should

The construction should have + past participle is used when talking about events in the past that did not happen or could/could not happen.
Used in indirect speech in relation to the past tense, if the verb should was used in direct speech in the sentence. In other cases, the verb should not used in the past tense. Instead, was/were supposed to is usually used.

Note

The constructions should have + past participle and to be supposed to are close in meaning and can often be interchanged. However, the design should have + past participle carries a greater connotation of criticism and regret, while the construction to be supposed to is less categorical and more common in colloquial speech.

Examples

It is cold outside. You should put on a jacket – It’s cold outside. You should wear a jacket. (advice)
He should have learned this lesson by now - He should have already learned this lesson. (we are talking about an event in the past that could have already happened)
They said we should not wait for them - They said that we should not wait for them. (indirect speech, provided that the verb should was used in direct speech)
Why don"t you call them? The car should be fixed by now - Why don’t you call them? The car should already be fixed. (probability)
Should I follow the instructions? – Should I follow the instructions? (please give advice or recommendation)
She was supposed to introduce me to him (NOT She should introduce me to him) – She had to introduce me to him. (we are talking about the past tense, in which case the expression was supposed to is used instead of the verb should)

#4 Modal verb Ought to

Uses of the verb Ought to

To express obligation, advice, recommendation.
To express the probability of something.

Features of the use of the verb Ought to

The construction is used in relation to the past time when the event did not occur.

Examples

You ought to listen to your parents - You must listen to your parents. (expression of obligation)
Hurry up! You ought not to miss your train – Hurry up! You mustn't miss your train. (advice, recommendation)
Ought we to start the speech now? – Should we start speaking now? (the speaker asks for advice)
His behavior ought to improve after this talk - His behavior should improve after this conversation. (probability expression)
The plane landed an hour ago. They ought to have gone through the customs by now – The plane landed an hour ago. They are already should have passed through customs. (design ought to have + past participle; The example shows that the action did not occur)

#5 Difference between Must and Have to

The verb Must is used to express personal feelings speaker. The verb Have to is used when speaking about facts and about necessity due to certain circumstances.
The verb Must is used when talking about the present or future, but not the past. The verb Have to is used in all tenses.
When forming negative and interrogative sentences, the verb Have to requires the use of auxiliary verbs do/does/did/will, etc.
Must not is used when it is important not to do something about we're talking about in a sentence. Do not have to is used when something is not needed, but it can be done (depending on the desire of the speaker).

Examples

You must change your diet to lose some weight - You must change your diet to lose weight. (personal opinion of the speaker)
You do not have to drink so much water - You may not drink so much water. (no need for this)
You must not drink so much water - You must not drink so much water. (this is a ban)
You have to turn left at the crossroads - You must turn left at the intersection. (not the speaker’s personal opinion, but a fact)

#6 Difference between Must and Should/Ought to

The verb Must expresses a higher degree of obligation. The verb Must is more often used in orders, regulations, etc. The verbs Should and Ought to are more often used in advice and recommendations.
In assumptions, the verbs Should and Ought to indicate a lower degree of confidence of the speaker than the verb Must.
In logical inferences and conclusions, the verb Must is used.

Examples

It is cold outside. You must wear a coat – It’s cold outside. You must put on your coat. (higher degree of obligation, order)
In weather like this you should wear a coat - In this weather you should wear a coat. (advice, recommendation)
The dinner must be ready now - Dinner must be ready. (high degree of confidence of the speaker)
The dinner should be ready now - Dinner should be ready. (lower degree of speaker's confidence, assumption)
Are they on holiday? They must be having a great time! -Are they on vacation? They must be having a great time! (logical conclusion, conclusion)

In English, must and have to both perform one function: they show the obligatory nature of a certain action. But despite their similarity, these verbs are used in different speech situations, require different auxiliary verbs and interact with tenses differently. Let's figure out the difference between must and have to.

Difference between must and have to

The modal verb must is much more personal than have to; it is used to express personal feelings and feelings. While have to is impersonal, as a rule, it is used when talking about events and facts.

I must go to work— I have to go to work.
We have to visit our aunt— We need to visit our aunt.

There is also a difference in the negative forms of verbs: mustn’t and don’t have to. If the negation “don’t have to” means that you simply don’t need to do something (although it is possible), then the use of the negation “mustn’t” is practically an order “not to do!”

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You don’t have to be there today! All would be done without you-You don't have to be there today. Everything will be done without you.
You mustn't be late- You can't be late.

When to use must

The first thing to remember about the modal verb must is that it does not have a past tense form; English grammar assumes that must is used only in the present and future and does not change its form. For the past tense we use had to (the past tense form of the modal verb have to).

You must visit a psychologist now- You should see a psychologist now.
She must visit a psychologist next Sunday - She must visit a psychologist next Sunday.

The verb must reflects an internal obligation, the need to do something. This verb can be used in written instructions, strong recommendations. This is best translated into Russian by the words “must” and “obliged”.

You must brush your teeth— You must brush your teeth.
You must sign these papers— You must sign these documents.

In addition, using the verb must you can convey an assumption/conclusion.

You must be bored- You're probably bored.
Kate must have known her- Kate must have known her.

When to use have to

The verb have to is used much more often in colloquial speech than must. It denotes the need to do something, which is determined not by internal necessity, but by external circumstances. Unlike must, the modal verb have to needs auxiliary verbs and can change tenses and change its form.

I have to go- I need to go.
I had to go- I had to go.
I will have to go- I'll have to go.

Examples with translation:

You must ask her about this situation“You should ask her about this situation.”
We must end it right now“We have to finish this now.”
You must build a boat to escape the island“You must build a boat to escape from this island.”
She must do her homework— She must do her homework.
We have to buy food and coffee— We need to buy food and coffee.
We had to use it right“We had to use it correctly.”
I will have to teach you how to be villains“I will have to teach you how to be a villain.”

Video about the difference between have to and must:

In English there is such a concept as may, must, should or be able to. Three of them are translated into Russian with the same word - “must”. They are precisely one of the most common confusions among Russian-speaking people. But what then is the difference should, if their values are approximately similar?

In fact, they are not very similar. They all translate as "should" but have different emotional meanings. Let's try to figure this out, what is the difference between should, must and have to.

Should

This modal verb is used when we give someone friendly advice or some kind of gentle recommendations. This can also be translated into Russian as “should”. When it's cold outside, we say to a close friend: "You should put on a jacket!" But at the same time, a friend can either listen to advice or do as he wants. That is, should does not imply any obligatory action.

I think, Mary should find a job. - I think Mary should find herself a job.
Jonh should listen to his parents more often. - John should listen to his parents more often.
You should be kinder to your children! They are so nice! - You should (you should) be kinder to your children. They are so cute!

In some cases should can take a cruder form, depending on the context in which it is used:

You should do what I ask! - You should (you must) do what I ask!

Using this modal verb, you can also ask for the same friendly advice or recommendation:

Should I buy that red dress? - Should I buy that red dress?

Must

What is the difference between should and must? The difference between should and must is that the second modal verb can strictly explain some obligatory action that someone is OBLIGED and MUST do. Often must is some kind of moral duty, for example, the duty to defend one's country or obey the law. That is, this modal verb is used when you talk about some of your own beliefs or generally accepted rules and laws.

Every man must think about the environment. - Every person is obliged to think about environment.
I am a soldier, and soldiers must follow instructions. - I am a soldier, and soldiers must follow instructions.
You must be stronger and forget about him! - You must be stronger and forget about him!

In negative sentences it acts as some kind of sharp, categorical prohibition to do something. Usually translated as "not allowed".

You must not lie to me! - You can't lie to me!
You are too weak, you must not smoke! - You are too weak, you cannot smoke!
Alice musn't be here, and you know that. - Alice cannot be here, and you know it.

Must is usually not used in the interrogative form and does not change tenses, for this there is the following word - have to.

Have to

This word is not a modal verb like the previous two, but is also translated into Russian as “must”. It is used when talking about some forced action: “I had to,” “I was forced.” Have to can also be translated as “to be forced”, “required”, “have to”.

Let's give simple examples in Russian.

If a person has poor eyesight, he has to wear glasses to see normally. Mary wanted to go out with her friends, but she had to stay at home because she had to look after her younger brother. Alex and Jessica quickly said goodbye because Alex had to leave town at five.

In all these cases, the English version uses have to.

She has a myopia. That's why she has to wear glasses. - She has myopia. That's why she wears (she has to wear) glasses.
Sorry, Jessica, I have to go now. My bus leaves the city at five o'clock. - Sorry, Jessica, I have to (I have to) go now. The bus leaves the city at five o'clock.

Unlike must in negative sentences, it means that there is no need to do something or that some action is not obligatory. Whereas must certainly means a categorical prohibition to do something.

You don"t have to help us with all this stuff. - You don’t have to (there’s no need) to help us with all this.
You didn't have to make a decision by yourself, so it's Ok, Lucy. “You didn’t have to decide everything yourself, so it’s okay, Lucy.”

Have to is used in interrogative sentences with auxiliary verbs to ask about the need to do something. Often translated into Russian with the word “need” or “necessary”.

Do I really have to learn history? - Do I really need to learn history?
Will I have to go shopping? - Do I need to go shopping?

Have to as an analogue of must

Depending on the time, have to can change and replace must in the past and future tenses.

Mary had been invited to the party, but she had to look after her younger brother. - Mary was invited to the party, but she had (she had to) look after her younger brother.
Actually, you had to turn right. - Actually, you should have (you should have) turned right.
Mike, you will have to do all housework, make meal, feed the cat and call us every day after your classes while we are not home. - Mike, you will have (you will have to) do all the housework, cook the food, feed the cat and call us every day after class while we are not home.

Since must is not used in the past or future, have to can replace it to show an obligation in the past or future, as shown in the previous sentences. Also used in interrogative sentences instead of must:

Do I have to follow all these rules? - Do I have to follow all these rules?

Ought to and should: what's the difference?

We have already discussed the difference between should, must and have to, but there is another modal verb that is similar in meaning to the verb should, but is much less common. They are very often confused; all of them, one might say, are almost similar. But there is still a slight difference in their use.

In many cases, they can replace each other, since both indicate advice or recommendation. However, should is used much more often in interrogative sentences and any formal or more polite advice. And ought to is more of an expression of an obligation based on some personal beliefs, a sharper remark to do something right.

Alice ought to ask her parents before making such decisions! - Alice should (it would have been more correct) to ask her parents before making such decisions.
Your ought to be more understanding to his problem. -You should be more understanding of his problems.

The verb ought is not used in the future tense, and most often the tense is clear from the context. It also doesn't change based on faces.

You ought to go with us tomorrow. - You should come with us tomorrow.

We can say that outgh to is the brother of the modal verb should, but with some shade of obligation. Although in any situation where ought to can be used, should can also be used.

In the article, we looked at the difference between should, must and have to and gave examples to better understand their meanings.