Translation guide
Expresses obligation or necessity. In Japanese, this is most commonly conveyed using the pattern 'must do' or 'have to do', formed by the negative conditional of a verb plus ならない/いけない, or by the double-negative なくては/なければ plus ならない/いけない. There are also shorter casual forms and other expressions for 'need to' or 'should'.
Expressing that something is required or must be done, often due to rules, duty, or circumstances.
Standard formal pattern meaning 'must do' or 'have to do'. Used in writing and formal speech. V is the negative stem (ない-form without ない).
明日までにレポートを提出しなければならない。
I have to submit the report by tomorrow.
Similar to なければならない, but slightly more subjective, often implying personal obligation or that it's bad if you don't. Very common in spoken Japanese.
もう行かなければいけない。
I have to go now.
Equivalent to なければいけない, but slightly more colloquial. Often contracted to なくちゃいけない in casual speech.
毎日勉強しなくてはいけない。
I have to study every day.
Formal pattern similar to なければならない, but slightly less common. Used in writing and formal contexts.
規則を守らなくてはならない。
We have to follow the rules.
Casual contraction of なければ, often used without いけない/ならない in informal speech. Can sound abrupt or friendly depending on context.
早く起きなきゃ。
I gotta wake up early.
Expressing that something is necessary, often for a purpose or to achieve a goal.
Literally 'there is a need to V'. More formal and objective than なければならない. Used in written and spoken Japanese.
もっと練習する必要がある。
I need to practice more.
Colloquial pattern meaning 'must' or 'have to'. Often used in spoken Japanese. Can be shortened to ないと in casual speech.
そろそろ帰らないといけない。
I have to go home soon.
Expressing that something is advisable or expected, but not strictly required.
Means 'had better' or 'should'. Softer than 'have to'. Used for giving advice.
病院に行ったほうがいいよ。
You should go to the hospital.
Expresses moral obligation or duty, 'should' or 'ought to'. Stronger than ほうがいい, but not as forceful as なければならない. Often used in formal contexts.
約束は守るべきだ。
You should keep your promises.
Both mean 'must' or 'have to', but ならない is more objective (rule, law), while いけない is more subjective (personal feeling, it's bad if not done). In practice, they are often interchangeable.
法律を守らなければならない。
We must obey the law.
もう帰らなければいけない。
I have to go home now.
English 'have to' can sometimes be used for strong advice, but in Japanese, using なければならない for advice can sound too forceful. Use ほうがいい or べきだ instead.
今すぐやらなければいけませんか？
Do I have to do it now?