Ways to express probability and possibility in Japanese

By | March 20, 2014

In this post I’d like to discuss a few ways to express probability and possibility in Japanese.

I think most of you already know about some of the more basic ways to express uncertainty in Japanese, for example:

  • かもしれない  (sometimes abbreviated as かも)
  • (じゃない) かな
  • でしょう (discussed here)
  • たぶん

These all can be used to convey various degrees of uncertainty (‘maybe’, ‘probably’, etc.) depending on context and tone of voice.

Let’s look at a few more advanced ways to express possibility. The word “possibility” can be translated as 可能性 (かのうせい),  which is derived from 可能(かのう), which roughly means “possible”. The antonym of 可能 is 不可能 (ふかのう), or “impossible”.

Here are few example sentences illustrating the use of 可能性.

  • このノートパソコンは新品なので壊れる可能性がないです。
  • This (computer) notebook is new (= just bought) so there is no possibility of it breaking.
  • いや、新品でも可能性はありますよ。
  • No, even new products have that possibility.
  • そうほ言っても、壊れる可能性がものすごく低いと思います。
  • Even saying that, I think the possibility of it breaking is very low.
  • 壊れる可能性が高いとは言ってません。
  • I’m not saying that the possibility of it breaking is high.

From these sentences you can see that ある/ない is used to express the existence of a possibility, and 低い/高い are used to express a low or high chance of something occurring.

Another word with similar meaning and usage is 確率(かくりつ), which is closer to English “probability” and to me has a more mathematical/technical feel to it.

  • 火星で暮らせる確率がきわめて低いです。
  • The probability of being able to live on Mars is extremely low.

You can use the following words to express a specific number.

  • パーセント(or %) = percent
  • 割(わり)= 10 percent  (discussed here)
  • ゼロ = zero (0 percent)

Here is an example sentence using the first two of these.

  • 「2割の確率」というのは、起こる可能性が20パーセントという意味なんです。
  • Saying “The probability is 20%” means that there is a 20% possibility of occurring.

Another way to say “possible” in Japanese is あり得る. It’s antonym is あり得ない, and this word is commonly used together with the word なんて (after either a verb or noun) to express something is not possible, either literally or  metaphorically.

  • やりたいことがひとつもないなんてありえない。
  • There is no way that there isn’t a single thing you want to do.
  • 銀行がつぶれるなんてありえない。
  • It’s impossible that a bank would go out of business.

A final expression that can be used to express possibility is “考えられる”. This literally means “Can think of”, and is sometimes used by police detectives when discussing  different possibilities.

  • 犯罪者がすでに日本を出たというのは,まず考えられませんね。
  • It seem’s unlikely that the criminal already left Japan.
  • しかし、共犯者がいたことは考えられるでしょう。
  • But there is a possibility there was a accomplice.




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2 thoughts on “Ways to express probability and possibility in Japanese

  1. mc

    Unless you’re showing a dialect, I think you meant to say ありえない instead of ありねい.
    I believe the pattern should be ことを考えられる (not ことは考えられる).
    Also if you’re going to count 考えられる in this discussion you can probably also consider 思われる e.g. 共犯者がいたことと思われる (It’s believed that there was an accomplice).
    But then this leads into the rabbit hole of even more forms of uncertainty such as だそう、のよう、みたいに、らしい and 絶対に. The whole language was built on the uncertainty principle. 😉

    1. locksleyu Post author

      Thanks for the comment and the corrections! I fixed ありねい since that was just a typo (:
      ことは考えられる was intentional, though what you said is also grammatically correct (and would be more natural in certain situations, possibly in my example as well).
      Good point about 思われる, that also fits in the same category as 考えられる。
      It’s hard to many these articles fully comprehensive, usually I just cover as much as I can in one or two sittings, but sometimes I write follow-up posts.


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