かもしれない is translatable as “maybe” or “might”. It expresses less probability than adding the volitional form of the auxiliary verb (だろう / でしょう) at the end of the sentence. (Think of だろう as ~80% certainty, whereas かもしれない is closer to 50% or lower).
While かもしれない can be learnt as a set phrase, it may help to see how it is formed grammatically, especially since we’ve already covered each of the components. But first of all, an example sentence:
| 彼はこのメールを読んだら怒るかもしれない。 |
| He might get angry if he reads this email. |
| それが世界新記録かもしれない！ |
| That might be a world record! |
Critical Connection Rule: When attaching かもしれない to nouns and na-adjectives, do not use the auxiliary verb だ. It attaches directly to the word (e.g., 危険かもしれない, NOT 危険だかもしれない).
かもしれない consists of two particles, か and も, and the negative potential form of the verb “to know”, しる (知る). Essentially, the grammar involves making a question out of the clause and saying you don’t know. The inclusive particle も adds the nuance of “also” (i.e., you can’t know if it’s also…).
| 危険かも知れない。 |
| It might be dangerous. |
Literally: I can’t know if it is also dangerous.
| やってみると楽しいかもしれない。 |
| If you give it a try you might enjoy it. |
| 先週の授業でこの単語を習ったかもしれない。 |
| We might have learnt this vocabulary in the lesson last week. |
In casual conversation, the phrase is very often abbreviated to simply かも.
| あの人を知っているかも。 |
| I think I might know that person over there. |
Conversely, because the final verb in かもしれない is just the potential form of the verb しる, you can change the verb ending to create the polite form.
| 重要なので、明確に説明したほうがいいかもしれません。 |
| It’s important so you should probably explain clearly. |