すでに・もう・今更 | Differences, Usage, and Nuances in Japanese

Three ways to express 'already,' 'by now,' and 'at this point': factual completion, speaker perception, and irreversibility

Category: Concepts & Distinctions

What are the differences between すでに (sudeni), もう (mou), and 今更 (imasara)?

These are three adverbs that, at first glance, all seem to indicate that something has already happened or that it is “already too late.”

In general:

• すでに (written as 既に) emphasizes that an action took place before a certain reference point;

• もう, on the other hand, indicates that a certain state has already been reached or is no longer valid from this point onward;

• 今更 means “now that it’s too late” or “at this point,” referring to doing or saying something when it is no longer of any use.

In other words:

• すでに looks back to the past from a reference point;

• もう focuses on a state that has already been reached in the present;

• 今更 implies that the appropriate time has already passed.

This difference in perspective is also reflected in register and tone: すでに is typical of formal or written language, もう is the everyday choice (often colloquial and even emotional), while 今更 carries a nuance of belatedness and is frequently used in contexts involving apologies or regret.

The table below summarizes their main differences.

In the following sections, we will examine each of these adverbs in detail before comparing them directly and drawing some overall conclusions.

Difference Between すでに (sudeni), もう (mou), and 今更 (imasara) – Meaning, Usage, and Contexts

すでに, もう, and 今更 are three adverbs that are often translated as “already” or “by now” in English.

Although they overlap in their basic meaning in some cases, they are not interchangeable in every context.

The differences mainly concern register (formal vs. informal), temporal nuances and usage, as well as some additional meanings of もう.

As we did with other time expressions such as 後で・後に・後は, we will examine the meaning of each one, the contexts in which they are most appropriately used, and the nuances that distinguish them, before concluding with practical examples.

すでに (sudeni)

Meaning and usage

すでに is written with the kanji 既 and the kana に (既に). The character 既 originally conveys the idea of “having already been completely consumed.”

The etymology (字源) of 既 explains that the pictograph originally represented someone who “has finished eating everything”: it combines the image of a table full of food with that of a person turning away, indicating that the meal has been finished.

By extension, 既 in modern Japanese has come to mean “already (done)”. Thus, すでに (kun reading: sude-ni) conveys precisely the idea of “something that has already happened or already been completed.”

It is used mainly in formal contexts or written language.

In other words, すでに is perceived as more refined or literary vocabulary, often used in documents, news reports, business language, or formal narratives rather than in everyday conversation.

As an adverb, すでに means “already,” emphasizing that an event occurred before a certain reference point in time.

Unlike もう, すでに is not used with the meaning of “no longer.” It appears only in affirmative contexts.

According to the Daijisen, すでに indicates that “an action has already been completed in the past” or that “at a certain point, a particular state had already been reached.”

For example: 彼はすでに大人だ - “Kare wa sudeni otona da” means “He is already an adult (relative to the reference point).”

Within the sentence, like もう, it is placed before the verb or adjective.

It is usually used with the past tense or the 〜ている form to express actions that have already been completed.

For example: 会議はすでに始まっている。- “The meeting has already begun.”

すでに may also precede expressions such as 「…のはすでに」 or 「…とはすでに」. It is not used in negative expressions meaning “no longer” (in that case, もう is the correct choice).

Temporal nuance

From a temporal perspective, すでに indicates that something had happened before a particular point in time.

In other words, it emphasizes that the event had already been completed at a certain moment in the past.

For example, in すでに終わった, the completion precedes the present moment or another event.

Another example: その件はすでに決着がついている – “That matter has already been settled.”

In short, すでに refers to a temporal relationship viewed from a past perspective.

The idea of “already / irreversibility”

The use of すでに often carries the idea that the situation can no longer be changed, conveying the sense that “it is already too late.”

A typical example is the idiomatic expression: 時、すでに遅し – “It is already too late.” - (literally, “The time, already, is late.”), which emphasizes that the opportunity to act has passed.

In sentences like this, すでに indicates that the current state is the definitive result of something that has already happened.

Typical usage in sentences

すでに often appears at the beginning of a sentence to emphasize that something was already true earlier than one might expect. Its use is therefore typical of objective statements of fact.

It is usually used with verbs in the past tense or forms indicating a completed state.

Context, register, and tone

すでに is typically used in formal or written language. It carries no emotional coloring and sounds neutral and detached.

For this reason, it is common in newspapers, documents, manuals, and similar contexts, whereas もう is generally preferred in informal speech.

In terms of tone, すでに does not express surprise or frustration: it is simply factual, corresponding to “already beforehand” in a straightforward, matter-of-fact way.

For example お知らせはすでに配られました。- “The notices have already been distributed.”

This could be considered a typical example of a standard informational sentence.

Examples

私はその時すでに知っていました。

彼女は来たときにはすでに帰っていた。

すでに述べたように, これが重要です。

Note: In colloquial contexts, すでに is often replaced by とっくに to express “a long time ago already” (emphasizing that a considerable amount of time has passed), or by もう, as we will see shortly.

For example, その問題はとっくに解決したよ = “I solved that problem a long time ago.”

とっくに is informal and emphasizes that the event happened quite a long time earlier, whereas すでに remains neutral regarding “how long before” and is simply the more formal expression.

もう (mō)

Meaning and usage

もう is usually written in hiragana (もう) and has no modern kanji of its own. Etymologically, it derives from the Old Japanese word いま (“now”) through a phonetic change.

In fact, もう is the result of the phonetic evolution of いま, carrying the implicit meaning of “by now” or “at this point.”

In practice, もう corresponds to “by now,” that is, “already at this point.”

In public or formal contexts, however, synonyms such as 既に and 最早 (もはや) are found, both of which share the same sense of “by now.”

もう is a highly versatile adverb commonly used in both colloquial and standard formal contexts (neutral register) in everyday Japanese.

As mentioned earlier, its basic meaning is also “already,” but its usage is broader than that of すでに.

Thus, the adverb もう has two fundamental uses:

• with verbs in the past tense, it means “already” (as in English “I’ve already done it”);

• with verbs in the negative form, it means “no longer” (as in “not… anymore”).

In other words, もう indicates that, from the current point of view, something has already been achieved or can no longer occur.

For example: もう宿題を終えた。- “I’ve already finished my homework.”

Or: もう食べられない。 - “I can’t eat anymore.”

As an adverb, it is normally placed before the verb or adjective it modifies.

The Daijisen states that もう “indicates that an action has already been completed” or that a certain state has already been reached.

In addition, もう can also mean “soon” when it precedes a future event (e.g. もう終わりますから… - “It’s about to finish…”), and it can add emphasis to situations or emotions (for example, in the sentence もうごめんだ - “I’ve had enough.”).

In short, もう is a very common adverb that adds temporal information related to “already” and is often used together with the past tense or negative forms.

It is also worth noting that it can function as an interjection expressing frustration, for example もういい！ “That’s enough!”

The main usages and nuances of もう can be summarized as follows:

• “Already” (affirmative past): In affirmative past-tense sentences, もう means “already (completed).”

  Example: もう食べました。– “I’ve already eaten.”

  Here, もう indicates that the action was completed before the present moment, much like すでに, but in a more colloquial register. It often also suggests “earlier than expected” (there is an implicit sense of surprise or exceeded expectations, as we will see below).

• Questions meaning “already?”: もう is commonly used in questions to ask whether something has already happened.

  Example: もう来たの？ – “Have you already arrived?”

  In English, this corresponds to “already…?” and often expresses surprise that the action happened so soon.

  Another example: もう宿題した？ – “Have you already done your homework?”

• “No longer / not… anymore” (negative sentences): In negative sentences, もう takes on the meaning of “no longer” or “not… anymore.”

  For example: 時間がもうありません。– “There is no more time.”

  Or: もう待てない！– “I can’t wait any longer!”

  Here, もう indicates that a previous condition has come to an end: there is now no time left, the possibility of waiting has ended, and so on.

  (Note: すでに is rarely used in negative sentences of this kind; in formal contexts, 「もはや」 is preferred for “no longer / by now no longer.” For example: もはや手遅れだ – “It’s too late now.”)

• “Another / one more” (quantity or repetition): When followed by a counter, もう can mean *“another” or *“one more.”

  For example: もう一つケーキを食べてもいい？ – “Can I have another piece of cake?”

  Or: もう一度お願いします。 – “One more time, please.”

  In these sentences, もう indicates addition or repetition (another item, another time). すでに cannot be used in this way—it is limited to the temporal meaning of “already.”

• “Soon / before long” (temporal proximity): In expressions such as 「もうすぐ」 (mō sugu), もう means “soon” or “before long.”

  Example: もうすぐ夏休みだ。 – “Summer vacation is just around the corner.”

  Again, すでに would not be used here; this nuance is unique to もう.

• Exclamation of frustration: On its own, もう can also function as an exclamation expressing frustration or impatience, similar to “Ugh!” or “Enough!” in English.

  For example: もう！, when said with the appropriate intonation, means “Ugh, enough already!” (This usage goes beyond the temporal meaning of “already,” but it is worth noting because it is common in colloquial speech.)

Temporal nuance

From a temporal point of view, もう marks the attainment of a new state from the present onward. In other words, it means “by now, this has already happened…”

Unlike すでに, which emphasizes that something had already happened beforehand, もう indicates that the situation is already true at the present moment.

For example: もう終わりました。- “It’s already over.” means “From the perspective of now, it has already finished.”

Thus, もう highlights the speaker’s viewpoint of “now”: it is used when something is already true at the present moment.

Context, register, and tone

もう is extremely common in spoken Japanese and in everyday writing.

Unlike すでに (which is more neutral and formal), もう belongs to the colloquial register and can carry emotional or emphatic nuances.

It can appear in simple statements but also in exclamatory sentences (especially with tones of frustration or regret).

For example, in everyday conversation we might say 「もう行ったの？」 - “Have you already gone?”, or express exasperation with 「もういいよ」 - “Alright, that’s enough.”

もう can be used at virtually every language level (colloquial, standard polite with 〜です and 〜ました), but in informal speech it is the natural choice for “already” and “no longer.”

In short, もう is extremely flexible and very common in spoken Japanese. It is introduced from the very beginning of Japanese study (JLPT N5) because it covers everyday situations, whereas すでに tends to appear at more advanced levels (around JLPT N3), reflecting its more formal and written usage.

Furthermore, もう often carries an emotional tone: depending on the context, it may convey surprise (“Already?!”), relief, frustration, and so on, whereas すでに generally does not, being more neutral and descriptive.

Examples

もう宿題を終えた。

お腹がいっぱいで、もう食べられない。

もういいから、ほっといて！

今更 (imasara)

Meaning and usage

今更 is composed of the kanji 今 (“now”) and 更 (“again, further”).

Literally, it suggests “now, once again.”

Etymologically, 今更 is believed to derive from the older expression 今さらに, where 今 refers to the present moment and さらに carries the idea of “again,” “still,” or “anew.”

The figurative meaning therefore becomes “to do something now (at this point) that should have been done earlier.”

In practice, the combination of 今 (now) and 更 (again) conveys the idea that “it is now too late.”

The adverb 今更 means “it’s too late now” or “there’s no point anymore.”

It is used when something is done or said at a point when the appropriate opportunity has already been lost.

Its primary meaning is precisely this: “If it had happened earlier, things would have been different; now it is too late (遅すぎる).”

For example:

今更言ってもしかたがない - “There’s no point saying it now.”

Grammatically, four major uses can be distinguished:

• It is used in sentences whose predicate is grammatically affirmative but carries a strong rhetorical nuance, with a negative implication.

  For example: あなたはあの男とはきっぱり別れたはずなのに、今更なんで会おうとしているの。 - “I thought you had completely broken things off with that man, so why are you trying to see him again now, after all this time?”

• It is used with negative predicates to express the idea that “it is no longer possible,” “it can no longer be done,” “there is no point anymore,” and so on.

  For example: 今更契約を解消するわけにはいかない。- “At this point, it is no longer possible to terminate the contract.”

• In some contexts, it appears in sentences containing concessive forms such as ても or たところで, where the predicate is negative or expresses an undesirable outcome.

  For example: ガンがここまで進むと、今更手術をしても治らないと思います。- “If the cancer has progressed this far, I don’t think surgery would cure it anymore, even if it were performed now.”

• It appears in the idiomatic expression 今更ながら, which means *“even though it’s rather late to say this,” “only now do I realize,” or *“I’m only saying this now, but…”

  For example: 母親を失って10年、自分も親になってみて、今更ながら、親不孝だったことを反省しています。- “Ten years have passed since I lost my mother, and now that I have become a parent myself, I only now realize how unfilial I was.”

今更 is typically used when something can no longer be done, or when a state can no longer come about because of circumstances created by an earlier action.

The circumstances in question therefore refer to events that certainly did not happen recently.

Those circumstances may either be explicitly stated or simply understood from the context.

As a result, 今更 tends to sound out of place in a sentence such as:

今更その電車には乗れない。(??) - “I can’t catch that train anymore.” (??)

Here, the speaker is simply too late for a train, so 今更 falls outside its usual temporal scope.

In a context like this, もう is much more natural:

もうその電車には乗れない。

Temporal nuance

今更 carries a clear nuance of “too late” relative to what would have been the appropriate moment. It implies that the action (or information) comes after the useful opportunity has already passed.

It highlights the contrast between “what should have happened earlier” and “what is happening now.”

For example, the rhetorical question 今更そんなことを言うの？ means “You’re saying something like that now, at this point?”

In other words, the emphasis is neither on the past (as with すでに) nor on the present state (as with もう), but rather on the fact that “the right time has already passed.”

It is similar to English expressions such as “it’s too late now” or “at this point.”

Context, register, and tone

今更 is used when the speaker wants to emphasize that something is being done or said too late, often with a critical or regretful tone.

It can express regret, apology, or frustration. For example, in a belated New Year’s greeting such as 今更ですが、明けましておめでとうございます, the speaker wishes the other person a Happy New Year while acknowledging that the greeting is late.

It is not particularly formal or informal in itself: it is used in both spoken and written Japanese, often with a conversational tone when expressing frustration.

It is especially common in apologies or belated attempts to make amends, conveying ideas such as “I’m sorry,” or “Please forgive me…”

Examples

今更そんなことは言えない。

今更謝ったところで、彼女は許してくれないだろう。

今更ながら、先生の言葉の意味がよくわかりました。

Direct comparison and key differences

Let us now summarize the main differences between すでに, もう, and 今更.

Register and context

すでに is formal and typical of written Japanese.

もう is neutral to colloquial and typical of everyday spoken Japanese, although it is also perfectly natural in polite speech and formal conversation. It is part of standard modern Japanese.

今更 is likewise common in both spoken and written Japanese, but it carries a much stronger pragmatic nuance. Rather than simply indicating that something has “already” happened, it suggests that something is being done, said, or realized only now, often when the appropriate moment has already passed.

Temporal perspective

All three expressions can be translated as “already” in certain contexts, but すでに typically refers to an event that had already been completed before a given reference point (often implying “for some time already”), whereas もう covers both the recent past and the idea that something is already true at the present moment.

For example, 彼はすでに帰宅していた suggests that he had already returned home before a certain point in time, whereas 彼はもう帰宅していた may simply state that, by the time we looked for him, he was already home.

今更, on the other hand, does not merely indicate that something has already happened. Instead, it places the action or realization at a point perceived as too late: “by now,” “at this point,” or “after all this time.”

For this reason, it frequently appears in sentences where what is done now seems pointless, untimely, inappropriate, or simply too late. For example, 今更謝っても遅い means “It’s too late to apologize now” or “Even if you apologize now, it’s already too late.”

Tone and emotional nuance

すでに is neutral and factual: it simply presents something as having already happened, usually from an objective perspective. もう, by contrast, can express surprise or emphasis, highlighting how soon something has occurred.

For example, もう来たの？！ sounds surprised: “You’re here already?!”, whereas すでに来ましたか？ is a formal question that simply asks whether someone had already arrived (“Had they already arrived?”).

今更 adds yet another nuance, often conveying criticism, resignation, regret, or a sense of futility.

In a sentence such as 今更そんなことを言っても仕方がない, the point is not merely that something is being said “now,” but that saying it now serves no purpose anymore.

Likewise, in questions such as 今更なんで会おうとしているの, 今更 conveys the idea of “Why now, after everything that’s happened?”

Negative sentences

To express “not… anymore,” Japanese uses もう (＋ negative form) rather than すでに.

For example, もう会いません means “We won’t see each other anymore.”

すでに rarely appears with negative predicates; in formal contexts, もはや is generally preferred instead (e.g. もはや使われていない – “It is no longer used.”)

すでに itself is normally used with affirmative completed events. A construction such as すでに〜ない is uncommon and generally sounds unnatural unless ない is simply part of the predicate itself.

今更, by contrast, frequently occurs with negative predicates or concessive constructions followed by a negative outcome.

In sentences such as 今更言えない (“At this point I can’t say it anymore”) or 今更謝ったところで、許してもらえない (“Even if I apologized now, I wouldn’t be forgiven”), 今更 does not mean “not… anymore” in the grammatical sense of もう〜ない. Instead, it indicates that the appropriate moment has already passed.

Other extended meanings

もう has additional meanings besides “already,” as discussed above (“another / one more,” “soon,” and even as an interjection).

すでに is limited to the meaning of “already” or “already by that point.” It cannot be used with the meaning of “another” or “one more” (for example, “another book” is もう一冊, never すでに一冊).

On the other hand, in rare literary contexts, すでに can convey the idea of “almost” or “by a hair’s breadth” in expressions such as 「すでに〜ところだった」 (“was just about to…”), indicating that something nearly happened.

For example: 「既に危うく衝突するところだった」 – “They very nearly collided.” (The collision was avoided at the last moment.)

This usage is largely confined to literary contexts.

今更, meanwhile, has extended meanings that primarily relate to the speaker’s evaluation of when something takes place. It can indicate that an action is now pointless or too late (今更後悔しても遅い – “It’s too late to regret it now”), that a question would be embarrassing because it should have been asked earlier (今更聞けない – “At this point I can’t ask anymore”), or introduce a realization that has come only belatedly through the expression 今更ながら.

For example: 今更ながら、先生の言葉の意味がわかりました – “Only now do I truly understand the meaning of my teacher’s words.”

Typical collocations

すでに commonly appears in expressions such as すでに述べたように (“as already mentioned”), すでにご存知の通り (“as you already know”), and すでに完了しました (“it has already been completed”), all of which are typical of documents and formal discourse.

もう is ubiquitous in everyday speech: もういい (“That’s enough / That’s fine”), もう一杯どう？ (“Would you like another drink?”), もう遅いよ (“It’s already too late”), もう帰る時間だ (“It’s already time to go home”), and so on.

今更 frequently appears in expressions such as 今更言っても仕方がない (“There’s no point saying it now”), 今更聞けない (“At this point I can’t ask anymore”), 今更謝ったところで〜ない (“Even if I apologized now, …”), and 今更ながら (“Only now, even though it’s already late”).

Unlike もう, which can simply indicate that a new state has already been reached, 今更 almost always emphasizes the relationship between the present moment and an opportunity that has already passed.

Practical examples in comparison

To further illustrate the correct usage, here are some example sentences showing すでに, もう, and 今更 in different contexts.

Formal / written (すでに)

その研究についてはすでに多くの報告があります。

Conversational (もう)

その映画、もう見たよ。

Casual question (もう + surprise)

えっ、彼女はもう帰っちゃったの？！

Formal factual statement (すでに)

彼女は私が電話した時にはすでに帰宅していました。

Negative sentence (もう … ない)

私は彼とはもう会いません。

Negative sentence expressing lateness (今更)

今更そんなことは言えない。

”Another / one more” (もう expressing an additional quantity)

お腹がいっぱいだけど、ケーキをもう一切れ食べたい。

Irreversible situation (すでに* with the nuance of “already / too late”)

すでに手遅れだ。

Futile or belated action (今更 + たところで + negative)

今更謝ったところで、彼女は許してくれないだろう。

Present-time perspective (もう meaning “already / by now”)

結婚してもう20年になる。

A realization that comes late (今更ながら)

今更ながら、先生の言葉の意味がよくわかりました。

Conclusion

すでに, もう, and 今更 can all be translated as “already” or “by now” in certain contexts, but choosing the appropriate one depends on the situation. すでに (既に) looks back to the past (“already before…”) and is formal; もう focuses on the present (“already / by now”) and is the everyday choice; 今更 expresses the idea of “too late” or “at this point, there’s no point anymore.”

Keeping their differences in nuance in mind—especially in the case of もう, which can also mean “not… anymore,” “another / one more,” “soon,” and even function as an interjection—helps avoid confusion.

The distinction is most clearly understood by paying attention to both the temporal perspective and the register.

As a practical rule, in everyday conversation もう will almost always be the natural choice for expressing “already,” simply indicating that “it’s already done.” すでに, on the other hand, is mainly found in formal situations and written texts, where a higher register is required and the speaker wishes to emphasize that something had already been completed.

今更, meanwhile, introduces a sense of frustration or the futility of acting too late.

Furthermore, すでに refers to something that had already been completed before a reference point, whereas もう can also describe something that has become true right now, often with an element of surprise.

Thus, もう corresponds to everyday “already” (or “not… anymore” in negative sentences), while すでに serves as its more formal counterpart.

These differences become increasingly clear through exposure to authentic examples and regular language practice, so it is worth paying close attention to the context whenever you encounter すでに, もう, or 今更 in actual use.

Ultimately, choosing the correct adverb depends on the sentence’s temporal perspective and the degree of emphasis—or formality—the speaker wishes to convey.