もう vs まだ
JLPT N5 vocabulary · what is the difference?
These are not synonyms — they mark aspect, and each one flips meaning with negation. もう means "already" in a positive sentence and "no longer" in a negative one; まだ means "still" in a positive sentence and "not yet" in a negative one. So もう食べました is "I already ate", まだ食べていません is "I haven't eaten yet", まだあります is "there's still some", もうありません is "there's none left".
When to use each
もう
もう
Use もう when a change has already happened: positive means "already", negative means "no longer". It always points at a state that has arrived or run out.
もう昼ご飯を食べました。
もうひるごはんをたべました。
I've already eaten lunch.
お金はもうありません。
おかねはもうありません。
I don't have any money left.
まだ
まだ
Use まだ when the change has not happened yet: positive means "still", negative means "not yet". The negative almost always takes 〜ていません, not 〜ませんでした.
雨はまだ降っています。
あめはまだふっています。
It's still raining.
その映画はまだ見ていません。
そのえいがはまだみていません。
I haven't seen that movie yet.
Sentences where only one works
もう宿題をしましたか。いいえ、まだしていません。
もうしゅくだいをしましたか。いいえ、まだしていません。
Have you done your homework yet? No, not yet.
The question asks with もう (already?) and the "not yet" answer must use まだ plus 〜ていません. Swapping the two words is impossible here.
ビールはまだありますか。いいえ、もうありません。
ビールはまだありますか。いいえ、もうありません。
Is there still beer? No, it's all gone.
まだあります means some is left; the negative of that idea is もうありません, not まだありません.
もう子どもじゃありません。
もうこどもじゃありません。
I'm not a child any more.
With a negative, もう means "no longer" — a change that has happened. まだ子どもじゃありません would mean "not a child yet", which makes no sense for someone growing up.
彼はまだ来ていません。
かれはまだきていません。
He hasn't arrived yet.
まだ implies he is still expected. もう来ていません would mean he no longer comes at all — a completely different statement.
Common mistakes
まだ食べませんでした。
まだ食べていません。
This is the single most common まだ error. 〜ませんでした is a closed past — "I didn't eat, and that is the end of it". "Not yet" is an open present state, so Japanese uses まだ plus 〜ていません. To a native speaker まだ食べませんでした sounds self-contradictory.
まだお金がありません。 (said when your wallet has run empty)
もうお金がありません。
If the money has run out, the state has changed, so you need もう meaning "no longer". まだありません would mean the money has not arrived yet, for example while you are waiting to be paid.
もう終わっていません。
まだ終わっていません。
Learners reach for もう because the question used もう. But "not finished" is an unrealised change, which is always まだ. Answer a もう question with まだ whenever the answer is no.
Frequently asked questions
Is まだ just the negative form of もう?
No. Both work in positive and negative sentences; it is the meaning that flips. もう plus positive is already, もう plus negative is no longer, まだ plus positive is still, まだ plus negative is not yet. Learn the four boxes together and the pair stops being confusing.
Why can't I say まだ食べませんでした for "I haven't eaten yet"?
Because 〜ませんでした reports a finished past event, while "not yet" describes your situation right now. Japanese expresses that with まだ〜ていません. The same goes for まだ来ていません, まだ読んでいません and まだ決めていません.
Can I just answer a question with まだです?
Yes. まだです is a complete, natural answer meaning "not yet", and it is the usual reply to もう食べましたか. The matching positive answer is もう食べました, or simply はい. Note that もう has a second sense of "more" in the fixed patterns もう少し, もう一度 and もう一つ, where まだ never works.