〜なければならない

Meaning

〜なければならない means must do or have to do. It expresses an obligation, rule, or necessary action.

Formation

Start with the ない form of a verb, remove the final い, and add ければならない. 行かない becomes 行かなければならない, and 飲まない becomes 飲まなければならない.

Usage

Use this pattern for duties, rules, health needs, deadlines, and things that cannot be avoided. In polite speech, 〜なければなりません is common.

Nuance

This pattern sounds standard and somewhat formal. It is clear and suitable for school, work, written explanations, and polite conversation.

Comparison

〜なければいけない has a similar meaning but can sound a little more conversational. 〜なくてもいい is the opposite idea and means that you do not have to do something.

Common Mistakes

A common mistake is keeping the final い of the ない form. Say 行かなければなりません, not 行かないければなりません. Another mistake is confusing it with 〜なくてもいい, which removes obligation.