Modals – have to, don’t have to

“Have to” is used to indicate that it is necessary to do something, although not obligatory. “Don’t/doesn’t have to” are used to indicate that there’s no compelling need to do something.

Affirmative	Negative	Interrogative	Interro-negative
I have to	I don’t have to	Do I have to	Don’t I have to?
You have to	You don’t have to	Do you have to?	Don’t you have to?
He, she, it has to	He, she, it doesn’t have to	Does he, she it have to?	Doesn’t he, she, it have to?
We have to	We don’t have to	Do we have to?	Don’t we have to?
You have to	You don’t have to	Do you have to?	Don’t you have to?
They have to	They don’t have to	Do they have to?	Don’t they have to?

“Have to” is used to express a need which is not an obligation. “Don’t/doesn’t have to” is used to indicate that something is unnecessary.

Use	Example
To express a need, a necessity	I have to go to the dentist for a check. She can’t go out. She has to do her homework.
To say that something is not necessary	You don’t have to go shopping. I’ve already bought everything.