JLPT N5 6 min read Updated May 17, 2026 Grammar pattern

なくてはならない

must do; have to do

Learn how to use なくてはならない, a JLPT N5 Japanese grammar point meaning must do; have to do, with structure, nuance, examples, mistakes, and comparisons.

Meaning
must do; have to do
Pattern
なくてはならない
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JLPT grammar
JLPT
N5

なくてはならない means must do; have to do. It is a JLPT N5 Japanese grammar pattern used to express a strong or formal necessity.

This grammar point appears often in beginner conversations, classroom Japanese, and JLPT-style questions. If you want to express a strong or formal necessity, なくてはならない is a useful pattern to learn because it helps you build natural basic sentences.

What does なくてはならない mean?

Use なくてはならない when you want to express a strong or formal necessity.

Natural translations include:

  • must do
  • have to do
  • must do; have to do

The exact English translation changes with context. Focus on the role of the grammar point in the sentence first, then choose the English phrase that sounds natural.

How to form なくてはならない

Verb ない-form without い + くてはならない

Examples of the pattern:

  • まもらなくてはならない
  • かんがえなくてはならない
  • かなくてはならない

Pay attention to the word form before and after the pattern. Many beginner mistakes happen because the meaning is understood, but the grammar is attached to the wrong form.

When is なくてはならない used?

Use なくてはならない in situations like:

  • formal rules
  • serious duties
  • written explanations

Tone and register:

  • formal or serious
  • Common in daily speech, textbook examples, and beginner JLPT questions

なくてはならない example sentences

約束やくそくまもらなくてはならない。
Promises must be kept.
obligation
わたしたちは時間じかん大切たいせつにしなくてはならない。
We must value time.
principle
試験しけんまえ復習ふくしゅうしなくてはならない。
I have to review before the exam.
study
このルールをまもらなくてはなりません。
You must follow this rule.
formal
もっと日本語にほんごかなくてはならない。
I must listen to more Japanese.
study

Read the Japanese sentence first, then check the English translation. Try to notice what the grammar point contributes: question, contrast, reason, time limit, suggestion, negation, comparison, or obligation.

Nuance of なくてはならない

The key nuance is a strong necessity that sounds more objective than casual obligation.

This matters because beginner Japanese often uses small words and endings to show meaning that English expresses with word order or helper verbs. For なくてはならない, the sentence can change a lot depending on placement and context.

For example:

  • In conversation, it helps the listener understand a strong necessity that sounds more objective than casual obligation.
  • Compared with なくてはいけない, it has a different job even when the English translation looks close.

なくてはならない vs なくてはいけない

Both なくてはならない and なくてはいけない can express related ideas, but they are different.

なくてはならない
Stronger and more formal; often used for rules, duties, and principles.
約束やくそくまもらなくてはならない。
Promises must be kept.
vs
なくてはいけない
More common in daily conversation; can sound less formal.
約束やくそくまもらなくてはいけない。
You have to keep promises.

If you are unsure which one to use, ask what the sentence is trying to do: ask a question, connect ideas, show a reason, mark time, make an invitation, compare two things, or express obligation.

Common mistakes with なくてはならない

友達ともだちに「なくてはならないよ」とう。
友達ともだちには「てよ」や「ないと」。
Using it too casually with close friends sounds overly formal and stiff.
まもるなくてはならない
まもらなくてはならない
Forgetting the negative verb base (ない-form without い + くて...).
Trying to conjugate ならない as the negative of なる.
Memorize なくてはならない as a fixed expression for formal obligation.
Confusing ならない with the “become” negative breaks the set phrase.

A good study habit is to write one short sentence and then change only the grammar point. This makes the difference between similar patterns easier to feel.

Is なくてはならない on the JLPT?

N5

Yes. なくてはならない is commonly taught as JLPT N5 grammar.

That means learners should be able to:

  • recognize it in reading
  • understand its nuance in context
  • use it in simple original sentences

For test preparation, do not only memorize the English gloss. Practice identifying the words around the grammar point, because JLPT questions often test structure and context together.

Practice questions for なくてはならない

Try making your own sentences with these prompts:

1 Say rules must be followed. obligation
2 Say you must review before the test. study
3 Say we must value time. principle

Keep the sentences short at first. Once the form feels natural, add time words, places, reasons, or contrast to make the sentence more realistic.

Learning path for なくてはならない

Use なくてはならない as part of your JLPT N5 request, permission, prohibition, and obligation grammar toolkit. Check the social force of the sentence: request, invitation, permission, prohibition, advice, or necessity. Then practice changing the ending to make the sentence softer, stronger, positive, or negative.

1
Learn the formation: attach なくてはならない to the correct verb form. Write one short sentence from memory.
2
Compare it with なくてはいけない. These patterns are close enough that choosing between them helps you understand the nuance.
3
Add ないといけない or なくちゃ to see how the basic meaning changes across formal and casual registers.
4
Write three short original sentences: one plain, one with a different subject or time word, and one that contrasts it with a related pattern.
  • なくてはいけない — contrasts request, permission, prohibition, advice, and obligation strength.
  • ないといけない — contrasts request, permission, prohibition, advice, and obligation strength.
  • なくちゃ — contrasts request, permission, prohibition, advice, and obligation strength.
  • ほうがいい — contrasts request, permission, prohibition, advice, and obligation strength.

Learn なくてはならない with Hane

If you want to review なくてはならない together with the related patterns above, Hane helps you practice Japanese in short, focused sessions.

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FAQ about なくてはならない

What does なくてはならない mean in Japanese?

なくてはならない means “must do; have to do” in Japanese. It is an N5 grammar point, and this lesson explains its formation, nuance, example sentences, common mistakes, and similar grammar.

Is なくてはならない on the JLPT?

なくてはならない is taught as N5 Japanese grammar in Hane's grammar lesson archive. Review it with examples, usage notes, and related N5 patterns.

How should I practice なくてはならない?

Read several example sentences, identify the form before and after なくてはならない, then make your own short sentences and compare it with nearby grammar points.

Practice this with Hane
Drill なくてはならない until it’s automatic.

Short, focused iOS sessions for grammar, kanji, vocabulary, reading, and JLPT review. Use this lesson with the JLPT prep app and the Japanese learning app overview.

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