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.
Because it's raining, I'll take an umbrella.
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.
The train was delayed, so I was late.
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.
Due to the typhoon, flights were canceled.
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.
This restaurant is delicious and cheap, so I come here often.
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.
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.
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.
The speaker states the reason as a noun or noun phrase, often using 理由 (reason) or 原因 (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.
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.
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.
Please close the window because it's cold. (direct)
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?
Why did you do that?
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.