How do you say "just curious" or "out of curiosity"?


In English, I often say "I'm just curious, but...". The best phrase I've come
up with for this in Japanese is

> 「[好奇心]{こうきしん}だけですが・・・」

but I've never heard a native speaker use this.

I recently saw 「なぜなのか気になりますが・・・」, but that sounds strange to me as well. Is
this just something that isn't said, or is there a totally regular phrasing
for this that I just haven't yet found?




To us native speakers, 「好奇心」 is a fairly big Sino-loanword and we do not use
it as often as English-speakers might use "curiosity" in informal situations
(or out on the street with a stranger, so to speak).

Natural ways to say "I'm just curious but ~~" or "Just out of curiosity, ~~"
would be:

**Informal** :

  * 「ちょっと[聞]{き}きたいんだけど～～」

  * 「[参考]{さんこう}までに～～」

  * 「参考までに聞くけど～～」, etc.

**More formal** :

  * 「[少々]{しょうしょう}お[聞]{き}きしますが～～」

  * 「[参考]{さんこう}までに[伺]{うかが}いたいのですが～～」

In formal situations, you could use 「好奇心」 if you wanted to and say something
like 「ほんの好奇心から伺いますが～～」. 「ほんの」 means "just". "mere(ly)", etc.




To us native speakers, 「好奇心」 is a fairly big Sino-loanword and we do not use
it as often as English-speakers might use "curiosity" in informal situations
(or out on the street with a stranger, so to speak).

Natural ways to say "I'm just curious but ~~" or "Just out of curiosity, ~~"
would be:

**Informal** :

  * 「ちょっと[聞]{き}きたいんだけど～～」

  * 「[参考]{さんこう}までに～～」

  * 「参考までに聞くけど～～」, etc.

**More formal** :

  * 「[少々]{しょうしょう}お[聞]{き}きしますが～～」

  * 「[参考]{さんこう}までに[伺]{うかが}いたいのですが～～」

In formal situations, you could use 「好奇心」 if you wanted to and say something
like 「ほんの好奇心から伺いますが～～」. 「ほんの」 means "just". "mere(ly)", etc.

