Translation guide
Expressing uncertainty about how to handle, use, or react to something or someone. Japanese often uses phrases like どうしたらいいかわからない or 持て余す depending on the nuance.
The speaker is at a loss about what action to take regarding something.
A very common, natural way to say 'I don't know what to do with (it/this).' It focuses on the action to take.
この書類、どうしたらいいかわからない。
I don't know what to do with these documents.
Similar to どうしたらいいか, but slightly more formal or written. Both are interchangeable in most contexts.
この問題をどうすればいいかわからない。
I don't know what to do with this problem.
A more casual, conversational version. Often used when feeling lost or overwhelmed.
こんなにたくさんあって、どうしていいかわからない。
There's so much, I don't know what to do with it all.
The speaker doesn't know how to deal with someone, often because they are difficult, embarrassing, or unfamiliar.
Literally 'to have too much to handle.' Used when someone or something is more than you can manage, often implying annoyance or being at a loss.
彼の態度を持て余している。
I don't know what to do with his attitude.
Specifically about not knowing how to interact with someone.
あの子にどう接したらいいかわからない。
I don't know what to do with that kid / how to deal with that kid.
Implies being troubled or having difficulty handling someone/something. Stronger nuance of being at one's wits' end.
The speaker has too much of something (time, money, objects) and doesn't know how to utilize or get rid of it.
Literally 'troubled about how to use it.' Perfect for objects or resources you don't know how to use.
もらったけど、使い道に困っている。
I received it, but I don't know what to do with it.
Also works for objects or time when you have more than you can handle.
暇を持て余している。
I have too much time on my hands / I don't know what to do with my free time.
Specifically about not knowing how to dispose of something.
この粗大ゴミをどう処分したらいいかわからない。
I don't know what to do with this oversized trash.
The speaker is so surprised, shocked, or moved that they don't know how to respond.
Directly expresses not knowing how to react.
そのニュースにどう反応していいかわからなかった。
I didn't know what to do with that news / how to react to that news.
Literally 'words don't come out.' Used when you are at a loss for words, often due to strong emotion.
驚きのあまり、言葉が出なかった。
I was so surprised I didn't know what to say / what to do with myself.
All mean 'what should I do,' but どうしたらいい is most common in speech. どうすればいい is slightly more formal/written. どうしていい is casual and often implies being flustered.
どうしたらいいか教えて。
Tell me what to do.
どうすればいいかご存知ですか？
Do you know what should be done?
もうどうしていいかわかんない。
I just don't know what to do anymore.
Do not translate 'not know what to do with' word-for-word as 何をするかわからない or similar. That would mean 'I don't know what (someone) will do,' not the intended meaning of being at a loss.
I don't know what to do with that mischievous child.