# 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. JLPT level: N5 · Updated: 2026-05-17 · Canonical: https://hane-app.com/blog/n5-nakute-wa-naranai/ **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: - 守まもらなくてはならない - 考かんがえなくてはならない - 行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

約束やくそくは守まもらなくてはならない。

Promises must be kept.

obligation

私わたしたちは時間じかんを大切たいせつにしなくてはならない。

We must value time.

principle

試験しけんの前まえに復習ふくしゅうしなくてはならない。

I have to review before the exam.

study

このルールを守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を聞き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.

約束やくそくは守まもらなくてはならない。

Promises must be kept.

なくてはいけない

More common in daily conversation; can sound less formal.

約束やくそくを守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「来こなくてはならないよ」と言いう。

✅

友達ともだちには「来きてよ」や「来こないと」。

Using it too casually with close friends sounds overly formal and stiff.

❌

守まもるなくてはならない

✅

守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?

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.

Learn the formation: attach なくてはならない to the correct verb form. Write one short sentence from memory.

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.

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.

Write three short original sentences: one plain, one with a different subject or time word, and one that contrasts it with a related pattern.

## Related grammar to review next - [なくてはいけない](/blog/n5-nakute-wa-ikenai/) — contrasts request, permission, prohibition, advice, and obligation strength. - [ないといけない](/blog/n5-naito-ikenai/) — contrasts request, permission, prohibition, advice, and obligation strength. - [なくちゃ](/blog/n5-nakucha/) — contrasts request, permission, prohibition, advice, and obligation strength. - [ほうがいい](/blog/n5-hou-ga-ii/) — 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. Browse more lessons here: - [All grammar lessons](/blog/) - [JLPT N5 grammar lessons](/blog/n5/)