〜かもしれない: How to Say 'Might' or 'Maybe' in Japanese
What it means
かもしれない expresses possibility — it might be true, but the speaker isn't confident. You use it when you're guessing, leaving room for the opposite to be true. Think of it as "maybe" or "it could be that…": there's a real chance, but you wouldn't bet on it. The certainty level is fairly low, which makes it a polite, careful way to offer an opinion without sounding sure of yourself.
明日は雨が降るかもしれない。
あしたは あめが ふる かもしれない。
It might rain tomorrow.
ヤッタンはもう寝たかもしれません。
ヤッタンは もう ねた かもしれません。
Yattan might have already gone to sleep.
Past plain form (寝た) + かもしれません.
この問題は難しいかもしれないよ。
この もんだいは むずかしい かもしれないよ。
This problem might be hard.
How to form it
The base attaches to plain forms. The one thing to watch: with nouns and な-adjectives, you drop だ and use the bare stem — never 学生だかもしれない.
| Word type | What attaches | Example |
|---|---|---|
| Verb (plain) | dictionary / ない / た form | 降る → 降るかもしれない (might fall) |
| い-adjective | plain form (keep い) | 高い → 高いかもしれない (might be expensive) |
| Noun | bare noun (no だ) | 学生 → 学生かもしれない (might be a student) |
| な-adjective | bare stem (no だ) | 静か → 静かかもしれない (might be quiet) |
The ending itself has three registers: plain かもしれない, polite かもしれません, and the clipped, very casual かも (just lop off the rest).
Examples across word types
その店は今日は高いかもしれない。
その みせは きょうは たかい かもしれない。
That shop might be expensive today.
い-adjective: keep the い.
あの人はヤッタンの弟の先生かもしれません。
あの ひとは ヤッタンの おとうとの せんせい かもしれません。
That person might be Yattan's brother's teacher.
Noun + かもしれません — no だ before it.
夜の図書館は静かかもしれない。
よるの としょかんは しずか かもしれない。
The library might be quiet at night.
な-adjective: use the bare stem 静か, not 静かだ.
The casual かも
In everyday speech, people often just say かも and stop. It's friendly and soft — great for casual chats with friends.
モチ、それ間違ってるかも。
モチ、それ まちがってる かも。
Mochi, that might be wrong.
Casual かも after a plain verb.
先生、ちょっと遅れるかも。
せんせい、ちょっと おくれる かも。
Teacher, I might be a little late.
Even with 先生, casual かも is common in quick messages.
How sure are you? (certainty levels)
かもしれない sits at the low end of certainty. When you're more confident, reach for stronger words. From least to most certain:
- かもしれない — maybe / might. A real possibility, but you're unsure. (50% or less)
- でしょう / だろう — probably. You expect it's true. See 〜でしょう.
- はず — should / is supposed to be. You have a solid reason to expect it.
So 雨が降るかもしれない ("it might rain") is a weaker guess than 雨が降るでしょう ("it'll probably rain"), which is weaker than 雨が降るはず ("it should rain, based on what I know").
モチは来るかもしれないけど、わからない。
モチは くる かもしれないけど、わからない。
Mochi might come, but I don't know.
かもしれない leaves the door open both ways.
Common mistakes
- Leaving だ before かもしれない. With nouns and な-adjectives, drop だ: 学生かもしれない (✓), not 学生だかもしれない (✗).
- Treating it like "definitely." かもしれない is a guess, not a prediction you're sure of. If you're confident, use でしょう or はず instead.
- Changing the い-adjective ending. Keep the full plain form: 高いかもしれない (✓), not 高かもしれない (✗).
- Conjugating かもしれない itself for tense. Put the tense on the word before it: 寝たかもしれない ("might have slept"), not 寝るかもしれなかった for that meaning.
Quick recap
- かもしれない = "might / maybe" — a possibility you're unsure about.
- Attaches to plain verbs and い-adjectives, and the bare stem of nouns / な-adjectives (no だ).
- Polite かもしれません; very casual かも.
- Certainty ladder: かもしれない (maybe) < でしょう/だろう (probably) < はず (should).
Your turn
Choose the correct form with かもしれない.
Start the 5-question drill →Take the full N4 〜かもしれない drill →
Frequently asked questions
Do I use だ before かもしれない with nouns?
No. Drop だ and attach かもしれない to the bare noun: 学生かもしれない ('might be a student'). The same goes for な-adjectives: 静かかもしれない.
What's the difference between かもしれない and でしょう?
かもしれない is a weaker guess ('maybe,' around 50% or less). でしょう/だろう means 'probably' — you expect it to be true. はず is stronger still ('should be'). They form a certainty ladder.
Is かも rude?
Not at all — かも is just very casual. It's perfect among friends or in quick messages, but in formal situations use かもしれません.
How do I say 'might have done' something?
Put the verb in past plain form before かもしれない: 食べたかもしれない ('might have eaten'). The tense lives on the verb, not on かもしれない.