Should vs Must: Difference and Comparison

Some words can be used interchangeably without changing the sentence’s meaning, but some can be used interchangeably but affect the sentence’s meaning.

Should and Must are two similar words that can be used interchangeably in a sentence, but both of them mean different in a sentence.

Key Takeaways

1. Should and Must are both modal verbs that are used to indicate obligation or necessity.
2. Should is used to indicate a recommendation or a suggestion, while Must is used to indicate a necessity or an obligation.
3. Should is less forceful than Must and implies that there is a choice, while Must implies that there is no choice and the action is necessary.

Should vs Must

The difference between Should and Must is that Should is the past form of shall and an auxiliary verb used in a sentence to give suggestions or advice. In contrast, Must is also an auxiliary verb, but it is used in the sentence to suggest what is compulsory to be done.

Should is the past form of shall and is used as an auxiliary verb in a sentence. It is used in a sentence to give suggestions or advice and ask for suggestions. It can be used in present-tense sentences as well as future-tense sentences.

Must is also an auxiliary verb. It is used in necessary sentences or if you are sure about something to be accurate and for a strong recommendation. It shows obligation and is used to give compulsory suggestions to be done. It is also used in law and order sentences to show obligations.

Comparison Table

Parameters of Comparison	Should	Must
Meaning	It is the past form of shall that indicates duties or responsibilities.	It is a modal verb that indicates necessity or a task that needs to be executed.
Nature	It is informal in nature.	It sounds formal when used in sentences.
Use	It is used to give or ask for suggestions and advice.	It is used to show obligations.
Degree of Emphasis	It shows less emphasis in the sentence.	It shows more emphasis in sentences.
Example	I should go to school.	We must follow traffic rules.

What is Should?

Should is a modal verb, and it is used with other verbs to give suggestions or ask for permission. It is the past form of Shall but used in different sentences other than the past form of Shall.

Should, when used in the sentence, shows responsibilities, duties, or the thing that is right to do.

It is used as an epistemic modal and a deontic modal, as ‘should’ is used to give suggestions and ask for permissions. It is used to show probability and sometimes expectations.

It is also used sometimes to express obligations but express less emphasis. There are many other uses of should in sentences.

Let’s discuss and see examples of uses of Should:-

1. It is used to tell or ask for the best choice from all available options. For example, You should do yoga instead of running and cycling.
2. It is used to show some chances of something happening. For example, She should be in the market at this time.
3. It is used to ask or give a reason for something. For example, Why should I do yoga instead of running and cycling?
4. It is used to give advice. For example, You should meet her at CCD in the evening.

Other than these examples, Should is used in many types of sentences that we can learn by practising daily.

What is Must?

Must is a modal verb and acts as a helping verb in sentences. It is used to express obligations; in sentences, it shows the necessity and what must be done.

Must is used formally in many sentences to give suggestions and in sentences to tell any rule of law.

It can be used interchangeably in the place of should without making grammatical mistakes, but it would change the context of sentences. It will suggest an obligation.

When used in sentences, it emphasizes the importance or need of the object.

Let’s discuss and see examples of uses of Must:-

1. It is used to express an object’s importance or necessity. For example, You must have protein in your diet.
2. It is used in sentences to apply prohibition. For example, You must not make noise in the class.
3. It is used to emphasize anything in the sentence. For example, You must tell her that she is very hard-working.
4. It is used to express intense action. For example, He must be the CEO of this company.

These are just a few examples. We can learn and practice many other uses of Must daily.

Main Differences Between Should and Must

1. The main difference between Should and Must is that Should is used in a sentence to give suggestions or ask permission, whereas Must is used to express obligations or show necessity.
2. It should is used informally in sentences. On the other hand, Must is a formal way of expressing something in a sentence.
3. When used in a sentence, it should show responsibilities and duties, but it must express importance, like a vital law or rule.
4. Should and Must can be used interchangeably, but if we use Should in a sentence, it will be a suggestion, and if we use Must instead of Should in the same sentence, it will be a compulsion task.
5. ‘Should’ is used to show a chance, ask permission, give advice, etc. On the other hand, ‘Must’ is used to express obligations, apply prohibition, express strong action, etc.

References

1. https://heinonline.org/hol-cgi-bin/get_pdf.cgi?handle=hein.journals/aklr43&section=38
2. https://academic.oup.com/slr/article-abstract/41/1/89/5203269