Translation guide
How to express doing something alone, without help, or independently in Japanese. The best choice depends on whether you mean 'alone' (solo), 'without help' (on one's own), or 'automatically' (by itself).
一人で住んでいます。
I live by myself.
自分でやりました。
I did it by myself.
To do something without other people, solo.
The most common and neutral way to say 'by oneself' meaning alone. Used for actions done solo.
彼は一人で住んでいます。
He lives by himself.
I went to see a movie by myself.
Same as 一人で but with the kanji 独, which emphasizes solitude or loneliness. Slightly more literary or emphatic.
独りで旅をするのが好きだ。
I like traveling by myself.
Literally 'just by oneself', emphasizing no one else is involved. Can overlap with 'without help'.
自分だけで決めないでください。
Don't decide by yourself.
To do something independently, without assistance.
The standard way to say 'by oneself' meaning without help. Emphasizes doing something personally.
宿題は自分でやりなさい。
Do your homework by yourself.
彼は自分で料理を作った。
He cooked by himself.
Emphasizes using one's own power or ability, often for overcoming difficulties. More formal or determined nuance.
彼は自力で問題を解決した。
He solved the problem by himself.
Similar to 自力で but more literary. Means 'by one's own efforts'.
彼は独力で事業を立ち上げた。
He started the business by himself.
Something happens on its own, without external cause.
Used for things that happen spontaneously or automatically, like a door closing by itself.
ドアがひとりでに閉まった。
The door closed by itself.
傷がひとりでに治った。
The wound healed by itself.
Means 'naturally' or 'by itself' in the sense of without human intervention. Often used for processes.
問題は自然に解決した。
The problem resolved itself.
Means 'automatically', often for machines or systems, but can be used figuratively.
更新は自動的に行われます。
Updates are performed by themselves.
一人で (hitori de) means 'alone' (solo), while 自分で (jibun de) means 'by oneself' (without help). Use 一人で when emphasizing the absence of others, and 自分で when emphasizing independence or personal effort.
Saying 自分で映画を見た (jibun de eiga o mita) sounds like you watched a movie without help, not that you went alone. Use 一人で for solo activities.