かな is put at the end of a sentence when you are wondering about something, mostly talking to yourself. It is casual, so it is used with plain forms among friends and family. かしら has the same meaning; it is traditionally used by women and is less common today. Said to a listener, かな can also work as a soft, indirect question.
§1Structure
Plain form + かな／かしら. Verb: 来るかな, 来たかな, 来ないかな. い-adjective: おいしいかな. な-adjective and noun: drop だ and attach directly — 静かかな, 学生かな (past: 静かだったかな, 学生だったかな). It also follows a question word sentence (どこに置いたかな) and the volitional form when you are deciding what to do (何を食べようかな). Negative + かな (〜ないかな) often expresses a hope that something will happen.
§2Examples
あしたは晴れるかな。
あしたははれるかな。
I wonder if it will be sunny tomorrow.
このケーキ、おいしいかな。
このケーキ、おいしいかな。
I wonder if this cake is good.
あの人は田中さんのお兄さんかな。
あのひとはたなかさんのおにいさんかな。
I wonder if that person is Tanaka-san's older brother.
この辺は夜も静かかな。
このへんはよるもしずかかな。
I wonder if this area is quiet at night, too.
リンさんはもう家に着いたかなと思って、電話しました。
リンさんはもういえについたかなとおもって、でんわしました。
I wondered if Linh had already got home, so I called her.
今晩、何を食べようかな。
こんばん、なにをたべようかな。
What shall I eat tonight, I wonder.
早くバスが来ないかな。
はやくバスがこないかな。
I hope the bus comes soon.
かぎはどこに置いたかしら。
かぎはどこにおいたかしら。
I wonder where I put my keys.
§3Common mistakes
- Keeping だ after a な-adjective or noun. ✕ 静かだかな / ✕ 学生だかな → ○ 静かかな / ○ 学生かな. Just like the question particle か, かな attaches directly, without だ.
- Using かな as a direct question to a teacher or boss. かな is casual and sounds like talking to yourself, so ✕ 先生、あした来ますかな is not appropriate. Ask politely with か or でしょうか: ○ 先生、あしたいらっしゃいますか。
- Reading 〜ないかな as a simple negative. 早く夏休みにならないかな does not mean 'I think summer vacation won't come'; it means 'I wish summer vacation would come soon.' The negative + かな pattern often expresses a hope.
§4How it's different from similar grammar
- 〜でしょう / 〜でしょうか (probably / I wonder, polite)
- 〜でしょうか is the polite way to wonder or to ask softly, and it can be used to a superior: あしたは雨でしょうか. かな is casual and mostly self-directed: あしたは雨かな. Use でしょうか in polite conversation and かな with friends or when thinking aloud.
- 〜か (question particle)
- か asks the listener directly and expects an answer: 田中さんはあした来ますか. かな shows that the speaker is wondering and does not demand an answer: 田中さんはあした来るかな. かな follows plain forms, while polite questions use です／ます + か.
§5How this shows up on the JLPT
In N4 grammar-form questions, かな appears as a sentence-final choice next to よ, ね and か; choose it when the speaker is wondering alone or deciding something (volitional form + かな). The connection rule (no だ before かな) can also be tested. In listening, かな and かしら show that the speaker is not sure, and 〜ないかな shows a hope, which often matters for questions about the speaker's feeling.
§6Quick check (3 questions)
1. What does the speaker mean? 「早く春にならないかな。」
はやくはるにならないかな。
2. Which sentence is correct?
3. The speaker is alone, deciding where to go on Sunday. Choose the correct form: 日曜日、どこへ＿＿かな。
にちようび、どこへ＿＿かな。