How to use must the right way


  • Something Necessary
    If it’s important to do something we use must to show it.
    e.g I must eat something now.
    Students must read their books if they need to pass.

  • Used for Emphasis
    I must say you are hardworking.
    You must see him.

  • Used for Probability
    If something is likely, true or certain we use must.
    e.g She must have gone home.
    You must be the the person they have sent.

  • Used for Obligation
    Have to’ and ‘must’ are both used to show obligation. However they are both used differently sometimes.
    We also use don’t have to to show lack of obligation
    You don’t have to pay to watch a movie it’s for charity purposes.

The Hack
Must is used to show that the obligation is by the speaker.
e.g We must go home it’s late. (the speaker inclusive)

Have to is used to show that the obligation is by someone else, not the speaker.
may be for rules and laws you can
e.g You have to do report to university on time.
I have to wear my helment at work.

  • Used for Prohibition
    Here you can use can’t and mustn’t (must not) to show that something is not allowed or is forbidden.
    You can’t smoke here.
    You mustn’t smoke here.


  • Can’t shows that it is against the rules.
  • Mustn’t shows that it is the speaker who is setting the rule.


We also use must as a noun.
E.g We eat bread as a must.
For you to go abroad having a visa is a must.