Difference Between Must and Shall

Must vs Shall

Must and shall are words in English language that have similar meanings. Both of them indicate the fact that something is mandatory and should be carried out as a duty. However, shall is used more in legal circles while must is used more often by common people. Many believe shall to be more formal of the two and fit for use in legal documents and contracts to stress a role or responsibility. This article takes a close look at these two words to find out if there are any differences between the two or not.


Shall is a verb that indicates a strong desire, intention, or assertion. It also refers to something that will take place in the future. It is also used to give an order or make a promise. It also indicates inevitability of something or an event. Take a look at the following examples to understand the meaning and usage of shall in English language. It is similar to will when used in first person.

• You shall complete the job by tomorrow (order)

• The train shall arrive tomorrow noon (future event)

• The justice shall be served (inevitability)

• The tenant shall make payment on every 5th day of a month (obligation)


Must is a word that indicates the necessity or requirement of something. It can be used as a noun when it means something not to be missed or overlooked. It is something that is obligatory in nature or is required by law. It is also used to express physical necessity. Must also helps in arriving at a conclusion by using logic. Here are some examples of must to make its used and meaning clear.

• You must register to be able to vote (requirement)

• We must have oxygen to survive (Physical necessity)

• You must not play after dark (command)

Must vs Shall

• Shall is used to indicate a legal requirement as in law and contracts.

• Shall indicates a duty imposed upon an individual.

• Must is used when the subject is inanimate.

• Must is used in everyday speech.

• Shall connotes weightiness and looks pretentious while must looks natural while speaking.