かもしれない means “might,” “may,” or “perhaps.” It is a JLPT N4 ending that marks something as possible but far from certain: 明日は雨かもしれません — “It might rain tomorrow.”
Literally it is か (“whether”) + も + 知れない (“can’t be known”): “whether it’s so can’t be known.” That origin explains the feeling. You are not predicting; you are opening a door to a possibility — often a fifty-fifty one, sometimes less.
かもしれない says “this could happen” without betting on it.
What does かもしれない mean?
Put かもしれない at the end of a statement and it becomes a possibility instead of a fact.
- 田中さんは来ない。 — Tanaka isn’t coming.
- 田中さんは来ないかもしれない。 — Tanaka might not come.
The polite form is かもしれません. In casual speech people shorten it to かも: 雨かも (“might rain”), もう寝たかも (“maybe they’re already asleep”). You’ll hear かも constantly among friends; in writing and polite talk, use the full form.
On the certainty scale, かもしれない sits low. でしょう means “probably,” and はずだ means “should, given the facts.” かもしれない only claims the thing is possible.
How to form かもしれない
かもしれない follows the plain form. The important exception: nouns and な-adjectives attach directly, with no だ and no な.
| Word type | Present | Past | Negative |
|---|---|---|---|
| Verb | 行くかもしれない | 行ったかもしれない | 行かないかもしれない |
| い-adjective | 高いかもしれない | 高かったかもしれない | 高くないかもしれない |
| な-adjective | 静かかもしれない | 静かだったかもしれない | 静かじゃないかもしれない |
| Noun | 雨かもしれない | 雨だったかもしれない | 雨じゃないかもしれない |
Only the present affirmative drops だ. In the past, だった stays: 雨だったかもしれない (“it may have been raining”).
かもしれない conjugates like an ordinary ない-adjective, so you can also say かもしれなかった (“might have been” in narration), though at N4 you mostly need かもしれない and かもしれません.
When is かもしれない used?
- Uncertain predictions: 午後から雪が降るかもしれません.
- Guesses about the past or present: 鍵は車の中かもしれない — “The key might be in the car.”
- Warnings and advice: add から and a suggestion — 込むかもしれないから、早く出よう.
- Softening your opinion: 少し高いかもしれませんね is a polite way to say “it’s a bit expensive,” especially when disagreeing with someone.
- Listing possibilities: 〜かもしれないし、〜かもしれない — “maybe this, maybe that.”
It often pairs with もしかしたら or もしかすると (“possibly”) at the start of the sentence, which underlines how uncertain you are.
かもしれない example sentences
明日は雨かもしれません。傘を持っていったほうがいいですよ。
It might rain tomorrow. You’d better take an umbrella.
田中さんは熱があると言っていたから、今日は来ないかもしれません。
Tanaka said he had a fever, so he might not come today.
電気が消えているね。もう寝たかもしれない。
The lights are off. Maybe they’ve already gone to bed.
このかばんは、ちょっと高いかもしれませんね。
This bag might be a little pricey.
もしかしたら、あの人は先生の奥さんかもしれない。
That person might be the teacher’s wife.
道が込んでいるかもしれないから、早めに出よう。
The roads might be busy, so let’s leave early.
行くかもしれないし、行かないかもしれない。まだ決めていない。
I might go, I might not. I haven’t decided yet.
Nuance of かもしれない
かもしれない is neutral about which outcome is likelier. That makes it the natural choice when you honestly don’t know, and also when you want to avoid sounding pushy. Japanese speakers often soften a clear opinion with かもしれない so the listener can disagree without friction. When a shop assistant says サイズが少し小さいかもしれません, they usually mean “it’s too small” — said gently.
Because it only claims possibility, you can stack opposite outcomes: 勝つかもしれないし、負けるかもしれない. You can’t do that with はずだ or でしょう, which each commit to one answer.
Politeness levels
There are three registers to keep apart. かもしれません is the standard polite form for teachers, customers, and colleagues. かもしれないです is also heard in polite conversation, but it sounds a little looser and is best avoided in formal writing or emails. かも is strictly casual — fine with friends, too relaxed for a job interview. On the JLPT, the polite form in dialogues is almost always かもしれません.
Casual かも as a reply
Casual かも can even stand alone as a reply. A：それ、おいしい？ B：うん、おいしいかも — “Yeah, it’s kind of good,” a hedge that sounds relaxed rather than unsure.
Asking, not stating: かもしれない is for your own guesses. To ask someone else “Will it rain?”, use 雨が降りますか or 雨でしょうか — not かもしれませんか.
かもしれない vs でしょう
Both are ways of not stating something as fact, but they sit at different levels of confidence.
A weather forecaster who says 雪が降るでしょう is making a call. One who says 雪が降るかもしれません is warning you it’s on the table. If you have a factual basis and feel sure, go one step further to はずだ.
Common mistakes with かもしれない
In the present affirmative, nouns attach directly. だ disappears.
な-adjectives also attach bare. The な you use before ので or はず doesn’t belong here.
かもしれない expresses your own uncertainty, so it doesn’t form a normal question. Ask with でしょうか or a plain ですか.
Is かもしれない on the JLPT?
Yes. かもしれない is a basic N4 grammar point. Expect grammar blanks testing the connection (雨かもしれない, not 雨だかもしれない) and listening items where a speaker says a plan “might” change — which means it isn’t confirmed.
At N4 you should be able to:
- Attach かもしれない to all word types, dropping だ after nouns and な-adjectives
- Recognise casual かも in conversation
- Rank かもしれない, でしょう, and はずだ by certainty
In listening, かもしれない is a trap signal: if someone says 行けないかもしれません, the answer to “Will they go?” is usually “not decided,” not “no.”
Practice questions for かもしれない
Show answer
今日、あの店は休みかもしれません。 — That shop might be closed today.
Show answer
まだ寝ているかも。 — Maybe they’re still asleep.
Show answer
電車が遅れるかもしれないから、早く出たほうがいいですよ。 — The train might be late, so you’d better leave early.
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この問題は簡単かもしれない。 — This problem might be easy.
Learning path for かもしれない
Related grammar to review next
- でしょう — “probably,” a step more confident than かもしれない.
- はずだ — “should be,” a conclusion from known facts, at the top of the scale.
- かな — casual “I wonder,” used when you’re thinking out loud rather than stating a possibility.
- らしい — “apparently,” a guess based on what you heard rather than pure possibility.
- もしかしたら — the adverb that sets up a かもしれない ending.
Learn かもしれない with Hane
Hane drills かもしれない against でしょう and はずだ, so you choose by how sure the speaker is. Practise N4 grammar in Hane.
FAQ about かもしれない
What does かもしれない (kamo shirenai) mean in Japanese?
かもしれない (kamo shirenai) means “might; perhaps”. It is JLPT N4 grammar. Put かもしれない at the end of a statement and it becomes a possibility instead of a fact.
How do you form かもしれない (kamo shirenai)?
かもしれない follows the plain form. The important exception: nouns and な-adjectives attach directly, with no だ and no な.
What is the difference between かもしれない and でしょう?
かもしれない: possible — maybe 50% or less. でしょう: probable — the speaker’s best guess.
What is an example sentence with かもしれない (kamo shirenai)?
明日は雨かもしれません。傘を持っていったほうがいいですよ。 — It might rain tomorrow. You’d better take an umbrella.