something is needn't i don't need something

The verb "to need" can be an auxiliary verb (followed by an infinitive verb) or the main verb in the sentence. If "to need" is an auxiliary verb you can use both "don´t need to" or "needn´t" : I don´t need to do it= I needn´t to do it But if "to need" is the main verb (followed by a noun or pronoun) the negative form must have the auxiliary "do", in that case you can only use "don´t need" example: I don´t need this (you cannot say "I needn´t this).

"Don't need to" means the same as "needn't" or "need not", but... "Don't need to" is all-purpose normal usage: "You don't need to walk, you can take the train." In the U.S., "needn't" sounds a little unusual and "need not" sounds more legal or formal: "Rule 5. Students need not attend class on Sunday."

Hi, there isn't any difference in the meaning. Both "don't need to" and 'Needn't' = need not / you don't have to Example: You needn't write anything else/ You don't need to write anything else in your email.

In interrogative sentences is more than one way to use "need"? Like this 1-Do you need to help her? 2-Need you to help her? Are both sentences correct?