なければならない・
These four forms express an obligation, practical necessity, or required state. Their underlying idea is that not doing something—or not being in the required state—is unacceptable.
How the construction works
Begin with the verb's negative form, but do not translate the whole sentence as a negative. The construction says, in effect, “if the action does not happen, that will not do,” so the natural English result is “must” or “have to.”
Rules and practical necessity
The obligation may come from a rule, from circumstances, or from a commitment already made.
図書館では、携帯電話の電源を切らなければなりません。
In the library, you must turn off your mobile phone.
AnalyzeThis is a rule, and the polite ending is appropriate for formal guidance.
明日は早いので、もう寝なくてはいけない。
I have an early start tomorrow, so I have to go to bed now.
AnalyzeHere the necessity comes from the speaker's circumstances rather than an official rule.
今日中に市役所へ行って、手続きをしなければいけません。
I have to go to city hall and complete the procedure today.
AnalyzeThe irregular verb uses the negative base しない, producing しなければ.
The four full combinations
Swipe sideways to compare every column.
| Negative condition | Final evaluation | Complete ending |
|---|---|---|
| なければ | ならない | なければならない |
| なくては | ならない | なくてはならない |
| なければ | いけない | なければいけない |
| なくては | いけない | なくてはいけない |
Do not assign four different English meanings to these combinations. Context and the source of the obligation matter more than the choice of one combination over another.
A required state
この仕事では、情報が正確でなければならない。
In this work, the information must be accurate.
AnalyzeNo action is required here. Accuracy itself is the necessary condition.
Required versus unnecessary
The target forms say that an action is required. By contrast, なくてもいい says that not doing it is acceptable, so the action is unnecessary.
明日は来なくてもいいです。
You do not have to come tomorrow.
AnalyzeMore examples
受験者は身分証明書を見せなくてはなりません。
Examinees must show identification.
Analyze雨なので、傘を持っていかなければいけない。
Since it is raining, I have to take an umbrella.
Analyze医者に言われたので、この薬を毎日飲まなくてはいけません。
My doctor told me to, so I have to take this medicine every day.
Analyze約束したから、明日までに本を返さなければならない。
I promised, so I must return the book by tomorrow.
Analyze昨日は仕事が多くて、残業しなければならなかった。
There was a lot of work yesterday, so I had to work overtime.
Analyze会議に出る人は、九時までに来なくてはならない。
Anyone attending the meeting must arrive by nine.
Analyze食品を扱う場所は、いつも清潔でなければなりません。
Places where food is handled must always be clean.
Analyze