〜かどうか: Whether or Not

You already know か as the particle that turns a statement into a yes/no question: 来ます → 来ますか ("does she come?"). かどうか is that very same interrogative か, but instead of firing the question at your listener, it holds the question open inside a larger sentence — "the question of whether she comes." This page looks at かどうか from the question side: what the か is doing, why どうか is tacked on, and how a question you would ask becomes a question you merely ponder, check, or worry about. The nuts and bolts of embedding — the exact frame, the copula rule, the contrast with quotation — are laid out on Embedded yes/no questions: 〜かどうか; here we stay on the interrogative particle itself.

か is still the question particle — it has just moved inside

Read these two side by side:

The か in 来るか is doing exactly what the か in 来ますか does — marking the clause as a yes/no interrogative. The difference is only who resolves it. At the end of a sentence, か hands the open question to the listener. Inside かどうか, no one resolves it on the spot; the open question becomes a noun‑like lump that the main verb then comments on — 分からない ("[I] don't know [it]"), 確かめる ("[I]'ll check [it]"), 心配だ ("[I]'m worried about [it]").

What どうか adds: it spells out the "or not"

The bare か already makes the clause a yes/no question. So why the extra どうか? Literally どうか is "or how," and it names the other fork of the yes/no split out loud: か ("…?") plus どうか ("…or how / or not") = "whether or not." It makes the "…or not" fully explicit and, honestly, gives the sentence a firmer, more deliberate ring.

You can often drop どうか and keep bare か, especially in speech — 受かるか心配だ, 合うか見てみて. Bare か is lighter; かどうか is the fuller, "…or not" spelled out. The full rule for when to drop it lives on the syntax page.

The embedded clause is in plain form — not the polite ますか

This is where the question‑side view earns its keep. You already know how to ask the yes/no question politely: 来ますか. But the moment that question goes inside a sentence, it sheds its politeness and drops to plain form: 来るかどうか, never ×来ますかどうか. Politeness lives on the main verb at the end (分かりません, 心配です) — the embedded question is always plain.

There is one spelling‑out detail that catches everyone — after a noun or na‑adjective, the plain copula だ is dropped before か (本当かどうか, not ×本当だかどうか), for the same reason it drops in a direct question (本当か, not 本当だか). That rule is worked through in full on the syntax page; the short version is no だ before this か.

Which verbs host it: knowing, checking, worrying

Because かどうか packages an unresolved question, it naturally attaches to predicates that operate on an open question rather than a settled fact — verbs of knowing, finding out, checking, hesitating, and worrying.

Indirectness: かどうか as a softener

There is a pragmatic payoff worth naming, because it is why natural speech reaches for かどうか so often. Turning a blunt direct question into an embedded one softens it. Compare asking someone flat‑out whether they will attend with wrapping the same question in かどうか教えていただけますか — the second is markedly more polite, because it does not put the person on the spot; it asks them to share the answer rather than demanding it. Indirect questions are a core politeness move — see Polite and indirect questions.

Yes/no only — a question word switches frames

One boundary to hold on to: かどうか is strictly for yes/no questions. The どうか works precisely because a yes/no question has exactly two forks — yes, or "or not." The moment a question word (何, どこ, 誰, いつ…) is inside the clause, the openness is already carried by that word, so you drop どうか and embed with plain か alone: 何を買うか決めた ("decided what to buy"), どこで会うかまだ決めてない ("haven't decided where to meet"). That wh‑embedding is its own topic — see Embedded wh‑questions with か.

Common mistakes

The through‑line: the inner clause is a plain‑form yes/no question, and か is its question mark. Keep the politeness at the end, don't leave だ in front of か, don't swap in と for a statement, and save どうか for genuine yes/no — a question word takes plain か by itself.

Key takeaways

• かどうか = "whether or not." The か is the ordinary yes/no question particle, held open inside a bigger sentence; どうか ("or how") spells out the "…or not."
• The embedded clause is plain form — 来るかどうか, never ×来ますかどうか; politeness lives on the main verb.
• It hosts verbs of knowing / checking / worrying (分かる, 確かめる, 迷う, 心配だ), and it softens a blunt question into a polite, indirect one.
• Yes/no only — a question word inside the clause drops どうか and embeds with plain か.
• For the embedding mechanics, the だ‑drop, and the と contrast in full, see Embedded yes/no questions: 〜かどうか.