Translation guide
Expresses 'because' or 'since' with a nuance of taking a known fact into account. Often used to provide a reason or context for a conclusion, suggestion, or situation.
The speaker presents a fact as a basis for what follows, often implying 'since this is the case'.
Attaches to a plain form clause. Emphasizes that the reason is an established fact or obvious. Often used when the speaker feels the listener should already know or agree.
もう遅いのだから、帰りましょう。
Given that it's already late, let's go home.
彼は専門家なのだから、意見を聞いたほうがいい。
Given that he's an expert, we should ask his opinion.
The speaker presents a condition and states what would be true or should be done under that condition.
Used to suppose a situation. 'If we assume that...'
彼が来ないとしたら、どうしよう。
Given that he might not come, what should we do?
Plain 〜から simply states a reason. 〜のだから adds the nuance that the reason is an obvious or known fact, often with an emotional tone (e.g., surprise, admonishment).
雨が降っているから、傘を持っていく。
Because it's raining, I'll take an umbrella. (neutral reason)
雨が降っているのだから、出かけるのはやめよう。
Given that it's raining (as you can see), let's not go out. (emphasizing the obvious fact)
Do not translate 'given that' word-for-word. There is no single Japanese equivalent; choose the pattern that matches the nuance of taking a fact into account or supposing a condition.
Used when the speaker accepts a premise and draws a strong conclusion or obligation from it. Often translates to 'since' or 'now that'.
約束した以上は、守らなければならない。
Given that you made a promise, you must keep it.
学生である以上、勉強するのは当然だ。
Given that you're a student, it's natural to study.
Similar to 以上, but often implies a stronger sense of resolve or determination based on the situation. 'Since it's come to this...'
やるからには、最後までやり遂げたい。
Given that I'm doing it, I want to see it through to the end.
Casual. Used to give a reason among others, often to justify a suggestion or action. 'And since...'
雨も降ってきたことだし、出かけるのはやめよう。
Given that it's started raining (among other things), let's not go out.
More formal/written version of としたら.
その話が本当だとすれば、大変なことだ。
Given that the story is true, it's a serious matter.