Translation guide
The English word 'necessary' expresses that something is required, essential, or unavoidable. In Japanese, the most common equivalent is 必要 (hitsuyou), but the natural way to express this depends on the grammatical structure and context. This guide covers the core adjective/noun 必要, related adjectives like 必須 and 不可欠, verb patterns such as 〜なければならない, and common set phrases.
Expressing that something is needed or required in a general sense, often as an adjective or noun.
The most common and versatile word for 'necessary'. Can be used as a noun or na-adjective. Often used in the pattern 〜が必要だ (〜 is necessary) or 〜する必要がある (it is necessary to do 〜).
Water is necessary for life.
Pattern meaning 'there is a need to do 〜' or 'it is necessary to 〜'. Attach to the dictionary form of a verb.
We need to leave early.
Pattern meaning 'there is no need to do 〜' or 'it is not necessary to 〜'. Attach to the dictionary form of a verb.
There's no need to rush.
Emphasizing that something is absolutely necessary, essential, or cannot be done without.
Expressing that an action is necessary or obligatory, often using verb constructions.
Standard pattern for 'must do' or 'have to do'. Attach to the negative stem of a verb (ない-form minus ない). Slightly formal but very common.
Expressing that something is bound to happen or cannot be avoided.
Expressing conditional necessity or contingency.
Means 'if necessary' or 'if needed'. A shortened form of 必要ならば.
必要 is the most general and common word for 'necessary'. 必須 implies a requirement or something mandatory, often used in rules or specifications. 不可欠 is stronger, meaning 'indispensable' or 'absolutely essential', and is often used in formal writing.
The English phrase 'necessary evil' is often translated as 必要悪 (ひつようあく), but this is a direct loan translation and may not be widely understood. Instead, rephrase the idea, e.g., 仕方のないこと (しかたのないこと, something that can't be helped) or 避けられない悪 (さけられないあく, unavoidable evil).
Is a visa necessary?
It is necessary to practice more.
Means 'indispensable' or 'essential'. Stronger than 必要. Often used in formal or written contexts.
Teamwork is essential for success.
Means 'mandatory' or 'required'. Often used for requirements, conditions, or items that are compulsory.
This document is required.
Means 'indispensable' or 'cannot be omitted'. A negative form of 欠かす (to omit). Common in everyday speech.
Smartphones are indispensable in modern life.
I have to submit the report by tomorrow.
Similar to 〜なければならない, but slightly more colloquial. Often shortened to 〜なくちゃ in casual speech.
I have to go now.
Another common pattern for obligation, often used in spoken Japanese. Can be shortened to 〜ないと.
I have to study every day.
Means 'inevitable' or 'necessary' in the sense of a logical or natural consequence. Often used in formal or academic contexts.
Change is inevitable.
Means 'unavoidable' or 'there is no other choice'. Used when a situation forces a certain action.
I will be absent due to unavoidable circumstances.
I'll help if necessary.
Means 'as necessary' or 'according to need'. More formal than 必要なら.
Please add materials as necessary.
It is necessary to make a reservation.
Sleep is necessary for health.