が必要だ (がひつようだ) — Need / Necessary
Expresses that something is needed or necessary. The needed item takes が; the person or situation that needs it takes は or に.
Structure
[Person/situation] は/に [Thing] が 必要だ／必要です
Examples
この仕事にはパソコンが必要です。
Kono shigoto ni wa pasokon ga hitsuyō desu.
A computer is necessary for this job.
この仕事には (for this job) + パソコンが必要
ビザを取るには、多くの書類が必要だ。
Biza o toru ni wa, ōku no shorui ga hitsuyō da.
Getting a visa requires many documents.
多くの書類が必要 = many documents are necessary
何が必要ですか？
Nani ga hitsuyō desu ka?
What do you need?
何が (what) + 必要ですか = what is necessary?
• 必要だ vs 要る (iru): 必要だ is more formal/written; • Question: 要る is casual spoken (何が要る？). • Note: 必要性 = necessity (noun). • Detail: 必要がある (hitsuyō ga aru) = it is necessary to [do verb]. • Not necessary: 必要はない / 必要がない / 必要ない (casual).
Commonly confused with
The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones が必要だ is tested against.
vs 必要がある (need to DO)
が必要だ takes a NOUN (お金が必要だ = I need money). 必要がある takes a VERB (行く必要がある = it is necessary to go). Choose by whether the thing needed is a thing or an action.
vs 要る (iru)
要る is the plain, everyday verb 'to need' (spoken). が必要だ is more formal/objective and common in writing and explanations.
More expressions
Study Japanese grammar on LenGaki
Everything on this page, free to browse
- 7,788 JLPT vocabulary words, N5 through N1, with readings and audio
- 2,057 kanji with on'yomi, kun'yomi and stroke-order practice
- 444 grammar points with examples and commonly-confused comparisons
- Full-length N5 and N4 mock exams, timed, with real listening audio
Get the Android app