What's the difference between 'must' and 'have to'.?

Question

I've got a few friends from Shang-Hai and they asked me this question - I pretended to be in a rush and told them I would tell them the next day!

Answer 1

Fear not! For I have the answer! Just forget the previous answers, I'm a qualified CELTA teacher and can brighten your day!

- 'Must' is a modal verb.
- 'Have to' is not a modal verb.

If they are being compared then obviously we are using them to convey 'obligation'.

They are 'mostly' interchangeable; however, there is a slight difference and the difference is related to 'authority' and who has it.

At the airport, you may hear:

Passengers 'must' check in one hour before take off.
The airport has the authority.

One person may comment:

Oh, did you hear that? We 'have to' check in one hour before take off.

Go ahead, impress your Shang-Hi-nese friends with this, you never know, perhaps they'll want to pay you for English lesson!

Answer 2

Basically both the words mean "should" with more or less the same meaning. However, the actual difference is: "Must' means something that you think you have to do "without any Option" and it emphasizes much about having to do with the "completion of a particular task" as compulsory or else you suffer from a loss, penalty or failure as consequences from the incompleted task. Whereas, "have to" is more liberally used substitute for the word "must", However, this doesn't validate the unavoidable or compulsory nature of the task as "must" does unless you think it is, that means you might just say :" I have to do this homework" but you still tend to ignore it or leave it for a future date because you know it's not that urgent or compulsory and that's where the whole idea of whether it should be "must" or just "have to" occurs as whatever it deems fit.

Answer 3

A good trick if you think two things might mean the same thing is to make up a bunch of phrases using one, and then see if the other could be substituted without changing the meaning.

In general they are interchageable, but note that "must" can only be used in the present tense.

For the previous responders, incidentally, "must" does denote something mandatory, not an option. "Should" is the auxiliary which denotes an option.

Answer 4

The difference is most clearly shown by the negative forms:
"You must not" means something is forbidden.
"You don't have to" means you can do it if you want to, but it is not obligatory.
"Must" in the positive form is merely stronger than "have to". If you must do soemthing, you do not really have a choice, but "have to" can be used where there might be other options, e.g., "You must get a bank account" leaves you no choice, but "If you want to get a credit card, you have to get a bank account" leaves you the choice of finding another way.

Answer 5

must- an order, someone telling you to do something

have to- something that needs to be done, and if it isnt, there will be negative consequences.

Eg. I must go to work, but I have to breathe.

Answer 6

i dont believe there is a difference unless the word is spell different but yeah thats not probably what they would want to hear.

Answer 7

Officially they both mean the same. Colloquially, they may be different.

Answer 8

'Have to' is when you have to take your girlfriend out to dinner not minding when and where you go to, 'must' is when you must pay for the meal or else all hell breaks loose.

Answer 9

must is more urgent? its more a ness for example, I MUST have a poo! -its is vital i have one
(i dont need one, i just have used a random example!)

and have to, is less vital? i HAVE TO have a poo, -i could have one but dont need to right now!!


lol i dont know if thats right, its all from my random thoughts

Answer 10

i guess when you say "most" is a suggestion...something you should do as an option...but if you say you "have to" sounds like a kind of order or obligation...doesn´t it?