〜かもしれない: How to Say 'Might' or 'Maybe' in Japanese
The stance it takes
かもしれない expresses possibility — it might be true, but the speaker isn't confident. You reach for it when you're guessing and want to leave 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. Because it commits to so little, it doubles as a soft, careful way to float 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.
What you attach it to
Unlike the other suppositions, かもしれない rests on nothing but the speaker's hunch — no evidence, no report, just what you attach in front of it. That front part is always a plain form. 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). In everyday speech people often just say かも and stop — it's friendly and soft, ideal for casual chats with friends.
How sure it sounds
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"). The difference is not just strength but attitude: かもしれない keeps the opposite outcome fully alive, whereas でしょう and はず lean toward one answer.
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.
In use
Across word types, the pattern holds — only the piece in front changes:
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.
And the casual かも in quick, spoken exchanges:
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.
Watch-outs
The one trap that actually catches learners is the connector before it — and a few smaller slips:
- 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.
The short version
- 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).
Practice it
Choose the correct form with かもしれない.
＿＿＿に入れるのに最もよいものを選びなさい。
Choose the grammar pattern that best completes the sentence.
明日は＿＿＿。
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.
Where 〜かもしれない fits
Shaky on this? Get these solid first
- 〜かどうか · N4 — 〜かどうか packs a yes/no question inside a bigger sentence: 来るかどうか分からない ('I don't know whether he'll come'). Learn the formation, noun and な-adjective rules, and how it differs from question-word + か.
Don't confuse it with
- 〜でしょう / 〜だろう · N5 — でしょう means 'probably' and, with a rising tone, 'right?'. Learn how it attaches to verbs, adjectives, and nouns, its casual form だろう, and why forecasts love it.
Hear it in a real conversation
See this pattern used naturally in a real-situation dialogue:
More N4 grammar to explore
Keep going with related patterns at the same level:
- Potential Form — The potential form means 'can / be able to': 食べる→食べられる, 書く→書ける, する→できる. Learn how to form it by verb group, the が particle shift, and ら-抜き.
- 〜ようになる — 〜ようになる describes a change — something that wasn't true or possible before, but now is. Learn the formation, nuance, and see 12 example sentences with a quick practice quiz.
- 〜始める・〜続ける・〜終わる・〜出す — Compound verbs of phase: add 〜始める, 〜続ける, 〜終わる, or 〜出す to a verb's ます-stem to say start, keep, finish, or suddenly begin doing something.
- 〜てある — 〜てある marks a state someone created on purpose: 窓が開けてある ('the window has been opened'). Learn the formation, the が particle, and how it differs from 〜ている.
- 〜ていく — 〜ていく has two big jobs: doing something then going (持っていく = take along), and a change continuing from now into the future (暑くなっていく). See how it mirrors 〜てくる.
- 〜てくる — 〜てくる has three core uses: go do something and come back, a change that has built up until now, and something approaching you in space or time. Learn each, plus how it differs from 〜ていく.