Translation guide
Expresses that something is absolutely necessary or essential. Japanese uses various adjectives, verbs, and set phrases depending on the nuance.
To say that something is so important that you cannot manage without it.
Literally 'cannot omit/neglect'. A very common and natural way to say something is indispensable.
水は生きるために欠かせない。
Water is indispensable for life.
To emphasize that something is a must, often in a more casual or emphatic way.
Literally 'absolutely necessary'. A straightforward, emphatic expression.
この仕事には経験が絶対に必要だ。
Experience is absolutely indispensable for this job.
To express that someone or something is so valuable that nothing else can take its place.
Literally 'a substitute won't work'. Used for people or things that are uniquely important.
彼女はチームにとって代わりがきかない人材だ。
She is an indispensable member of the team.
Both mean 'indispensable', but 欠かせない is slightly more common in everyday speech and writing. なくてはならない can sound a bit more emphatic or formal. They are often interchangeable.
健康は幸せに欠かせない。
Health is indispensable for happiness.
健康は幸せになくてはならない。
Health is indispensable for happiness.
The English word 'indispensable' is often translated directly as 不可欠な (ふかけつな), but this can sound stiff or overly formal in casual conversation. Use 欠かせない or なくてはならない for natural speech.
この道具は私の仕事に欠かせない。
This tool is indispensable for my work.
チームには良いコミュニケーションが欠かせない。
Good communication is indispensable in a team.
He is indispensable to this project.
Literally 'if it doesn't exist, it won't do'. A strong, common expression for necessity.
辞書は語学学習になくてはならない。
A dictionary is indispensable for language learning.
A more formal compound meaning 'necessary and indispensable'. Often used in writing or speeches.
この要素は成功に必要不可欠だ。
This element is indispensable for success.
Means 'mandatory' or 'essential'. Often used for requirements, items, or conditions.
この書類は申請に必須です。
This document is indispensable for the application.
From English 'must'. Casual and trendy, often used in marketing or informal speech.
このアプリは旅行にマストだよ。
This app is indispensable for travel.
Means 'irreplaceable' or 'precious'. Often used for loved ones or cherished things.
家族はかけがえのない存在です。
Family is indispensable.