〜でしょう／だろう

Meaning

でしょう conveys polite ‘probably’, while だろう is its plain and more direct counterpart.

Formation

1. Plain verb or i-adjective + でしょう／だろう: 来るでしょう, 寒いだろう.
2. After a noun or na-adjective: 雨でしょう／雨だろう, 静かでしょう／静かだろう.
3. For the past, change the preceding form: 来たでしょう, 学生だっただろう.

When to use it

Prediction or inference

Expresses a fairly confident assumption based on the situation or knowledge.

Expected agreement

With rising intonation, means ‘isn't that so?’ or ‘right?’.

Important notes

• In conversation, でしょう is often shortened to でしょ and だろう to だろ.
• だろう can sound quite confident and direct; でしょう is safer in neutral polite speech.

Common mistakes

• Do not add だ before でしょう: use 雨でしょう, not 雨だでしょう.
• Do not treat the form as pure uncertainty; the speaker normally considers the assumption well founded.

Similar grammar

• 〜ね〜ね shares information treated as known, while 〜でしょう states an assumption.
• 〜か〜か asks for an unknown fact, while 〜でしょう？ asks the listener to confirm an expectation.