Maybe/Possibility (かもしれない)

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:

彼かれはこのメールを読よんだら怒おこるかもしれない。

He might get angry if he reads this email.

それが世界新記録せかいしんきろくかもしれない！

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).

Why does it mean “might”?

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…).

危険きけんかも知しれない。

It might be dangerous.

Literally: I can’t know if it is also dangerous.

やってみると楽たのしいかもしれない。

If you give it a try you might enjoy it.

先週せんしゅうの授業じゅぎょうでこの単語たんごを習ならったかもしれない。

We might have learnt this vocabulary in the lesson last week.

Polite and Casual Forms

In casual conversation, the phrase is very often abbreviated to simply かも.

あの人ひとを知しっているかも。

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.

重要じゅうようなので、明確めいかくに説明せつめいしたほうがいいかもしれません。

It’s important so you should probably explain clearly.