Look at these two sentences:
A. 母が帰るまで掃除を続けてください。 → Please keep cleaning until Mom comes home.
B. 母が帰るまでに掃除を終えてください。 → Please finish cleaning before Mom comes home.
Sentence A: The cleaning action continues from now until Mom arrives. Sentence B: The cleaning must be done before Mom arrives — when you clean doesn't matter, as long as it's done by then.
The difference is just one particle: に.
まで = Continue Until a Point in Time
まで means the action keeps going continuously until that time.
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5時まで勉強する。 → Study until 5. (Studying continuously from now to 5.)
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終電まで飲んでいた。 → Was drinking until the last train. (Drinking the whole time.)
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雨が止むまで待ちましょう。 → Let's wait until the rain stops. (Keep waiting.)
Key point: Emphasizes the continuity of the action — from start to that time point, you're doing it the whole time.
までに = Complete Before a Point in Time
までに means finish the action before that point in time.
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5時までにレポートを出してください。 → Please submit the report by 5. (Write it whenever, just submit before 5.)
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来週の月曜日までに返事をください。 → Please reply by next Monday.
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明日までに準備しておく。 → Get everything prepared by tomorrow.
Key point: Emphasizes the deadline — the action doesn't need to be continuous, it just needs to be completed by then.
Side-by-Side Comparison
| まで | までに | |
|---|---|---|
| Meaning | Continue until... | Complete by... |
| Emphasis | Continuity of action | Deadline |
| Action type | Ongoing | One-time completion |
| 5 o'clock + study | Study until 5 (study the whole time) | Finish studying by 5 |
Visual Explanation
まで: =========> ● 5:00
doing it stop here
the whole
time
までに: ✓ ● 5:00
done at deadline
any point
Pairing Patterns
まで works well with continuous verbs:
- 待つ (wait), 勉強する (study), 働く (work)
までに works well with completion verbs:
- 終わる (finish), 出す (submit), 届ける (deliver)
Of course there are exceptions — the key is whether you mean "keep doing it" or "just get it done."
Common Exam Trap
3時＿＿ここに来てください。
A. まで B. までに
The answer is B. までに. 「来る」 is an instantaneous action — you can't "keep coming until 3 o'clock." The correct meaning is "please be here by 3."
Self-Test
Q1. What does 「お母さんが帰るまで遊んでいた」 mean?
Show answer
"I was playing until Mom came home." まで indicates the action continued until that point — playing the entire time until Mom returned.
Q2. Should 「金曜日＿＿レポートを出してください」 use まで or までに?
Show answer
までに. 「出す」 is an instantaneous completion action. This means "please submit the report by Friday" — it's a deadline.
Q3. What's the difference between 「朝から夜まで働いた」 and 「夜までに仕事を終わらせた」?
Show answer
「朝から夜まで働いた」 = Worked from morning until night (emphasizing continuous work). 「夜までに仕事を終わらせた」 = Finished the work before nighttime (emphasizing the deadline — doesn't matter when the work was done).
Summary
- まで = Action continues until a time point (the whole time)
- までに = Action completed before a time point (deadline)
- How to decide: "Am I doing it continuously until then, or just need it done by then?"
- Exam tip: Instantaneous verbs (来る, 出す, etc.) can only use までに