Translation guide
In Japanese, expressing reasons involves a variety of grammar patterns and phrases that differ by formality, emphasis, and context. The most common and versatile pattern is 〜から, but learners should also be aware of 〜ので for softer, more polite explanations, and 〜ため for formal or written contexts. This guide organizes the main ways to give reasons, from everyday conversation to formal writing.
The speaker provides a reason or cause for an action, state, or situation. This is the most basic and frequent use.
The most common and versatile way to say 'because'. Attaches to the plain form of verbs, adjectives, and nouns (with だ/です). Can be used in both casual and polite speech. The reason clause usually comes before the result.
雨が降っているから、傘を持って行きます。
Because it's raining, I'll take an umbrella.
疲れたから、早く寝ます。
I'm tired, so I'll go to bed early.
A slightly more formal and softer way to give a reason. Often used when the reason is an objective fact or when making polite requests. Attaches to the plain form, but nouns and na-adjectives take な before ので.
電車が遅れたので、遅刻しました。
The train was delayed, so I was late.
明日は休みなので、映画を見に行きませんか。
Since tomorrow is a day off, would you like to go see a movie?
Formal/literary expression for 'because of' or 'due to'. Often used in written Japanese, news, and official statements. Can also mean 'for the purpose of', but when used for reason, it attaches to the plain form. に is optional when expressing reason.
台風のため、飛行機が欠航になった。
Due to the typhoon, flights were canceled.
事故があったために、道路が渋滞している。
Because there was an accident, the road is congested.
The speaker gives more than one reason for something, often using structures like 'not only... but also...' or 'partly because...'.
Used to list multiple reasons or factors. Each clause ends with し (plain form + し). Implies there are other unstated reasons as well. Common in casual and polite speech.
このレストランは美味しいし、安いし、よく来ます。
This restaurant is delicious and cheap, so I come here often.
雨も降っているし、風も強いし、出かけたくない。
It's raining and windy, so I don't want to go out.
Means 'not only... but also...'. Used to add another reason or factor. More formal than 〜し.
値段が高いだけでなく、品質も悪い。
Not only is it expensive, but the quality is also poor.
The speaker asks for the reason or cause of something.
Formal/literary 'why'. Used in writing and formal speech. In casual conversation, なんで or どうして are more common.
なぜ遅れたのですか。
Why were you late?
Common 'why' in both casual and polite speech. Slightly softer than なんで.
Casual 'why'. Very common in everyday conversation. Can sound blunt or childish in formal settings.
なんでそんなことしたの？
Why did you do that?
The speaker states the reason as a noun or noun phrase, often using 理由 (reason) or 原因 (cause).
Means 'reason'. Used in phrases like 理由は〜です (The reason is...).
遅刻の理由は電車の遅れです。
The reason for being late is the train delay.
Means 'cause'. Used more for negative events or problems (e.g., accident cause, disease cause).
The speaker emphasizes that something is the very reason for a situation, often with a nuance of 'exactly because' or 'for that reason'.
Means 'precisely because'. Emphasizes that the reason is the main or only cause. Often used to express gratitude, apology, or strong feelings.
あなたがいたからこそ、成功できました。
It was precisely because you were here that we succeeded.
Means 'just because' (with a negative result). Implies that a single reason led to an unfortunate outcome. Often used for regret.
お金がないばかりに、旅行に行けない。
Just because I don't have money, I can't go on a trip.
から is the most general and can be used in any situation, but it can sound subjective or direct. ので is softer and more polite, often used when the reason is an objective fact or when making a request. ため is formal and common in writing; in speech, it can sound stiff. For everyday conversation, stick to から or ので.
寒いから窓を閉めてください。
Please close the window because it's cold. (direct)
寒いので窓を閉めてください。
Since it's cold, could you please close the window? (softer)
なぜ is formal and can sound stiff or interrogative in casual conversation. Use どうして or なんで with friends. なんで is very casual and can be rude if used with superiors.
どうして泣いているの？
Why are you crying?
事故の原因はスピードの出し過ぎです。
The cause of the accident was excessive speed.