〜までに

までに marks a DEADLINE: the action must happen (once) before or at that point in time. 金曜日までに出してください — you can submit it anytime, as long as it's no later than Friday.

You learned まで at N5: まで says the action continues CONTINUOUSLY up to that point. Compare: 五時まで働きます (I work straight through until 5 o'clock) and 五時までに帰ります (I'll go home by 5 — the action "go home" happens only once). The まで／までに pair comes up a lot on the N4 exam.

Before までに you can put a time noun or a verb in the dictionary form: 授業が始まるまでに (before class starts). This pattern often pairs with 〜ておく: 始まるまでに読んでおいてください (please read it in advance, before it starts).

Examples

• 金曜日(きんようび)までにレポートを出(だ)してください。

  Please submit the report by Friday.

• 十時(じゅうじ)までに家(いえ)に帰(かえ)らなければなりません。

  I have to be home by 10 o'clock.

• 授業(じゅぎょう)が始(はじ)まるまでに、この本(ほん)を読(よ)んでおいてください。

  Please read this book before class starts.

Related patterns

• 〜ておく
• 〜あいだ（に）