GrammarJLPT N5
→ whether (or not)
Whether (or not)
JLPT N5Compound particleNeutral
かどうか is used to embed a yes-or-no question inside a larger sentence, expressing the meaning "whether or not." It is attached to the plain form of a verb, adjective, or noun phrase and turns that clause into an indirect question that functions as a noun clause within the sentence. For example, if you want to say "I don't know whether he will come," you embed the yes-or-no question "Will he come?" using かどうか before the main verb. This differs from the single particle か used for embedded questions, which typically embeds information questions (who, what, where, etc.) rather than yes-or-no questions. While か alone can sometimes replace かどうか for yes-or-no embedded questions, かどうか is more explicit and natural in most contexts. The expression is used across all registers and is equally appropriate in casual conversation and formal writing.
Functions
#1 Expressing uncertainty about a fact
Structure
Verb (plain form) + かどうか + わからない / 知らない
明日、雨が降るかどうかわかりません。あした、 あめ が ふる かどうか わかりません。
Here かどうか embeds the yes-or-no question "Will it rain?" into the larger sentence as an indirect question. The clause 雨が降るかどうか functions as the object of わかりません, expressing that the speaker is uncertain about this binary outcome. This is the most common usage pattern, frequently paired with verbs like わからない, 知らない, or similar expressions of uncertainty.I don't know whether it will rain tomorrow or not.
Structures
- Verb (plain form)
- Verb (plain form) + かどうか + Main clause
- い-Adjective
- い-Adjective + かどうか + Main clause
- な-Adjective
- な-Adjective (stem) + (な/だった) + かどうか + Main clause
- Noun
- Noun + (な/だった) + かどうか + Main clause
Common mistakes
A common mistake is using the polite form (ます form) before かどうか — for example, saying 行きますかどうか instead of the correct 行くかどうか. Embedded clauses in Japanese require the plain form, not the polite form. Another frequent error is confusing かどうか with a single か. While か alone is used for embedded information questions like 何を食べるか (what to eat), かどうか is specifically for yes-or-no questions; saying 行くか instead of 行くかどうか can sound incomplete or ambiguous in many contexts. Learners also sometimes insert だ before かどうか after な-adjectives in the present affirmative, such as 元気だかどうか, when the correct forms are 元気なかどうか or 元気かどうか depending on formality. Finally, some learners try to use かどうか to embed questions with question words like 何 or どこ, but in those cases only か should be used, not かどうか.
Related
か (embedded question)かなかしらwhether～or～ (AかBか)のかかもしれない