割り勘（わりかん、warikan）
- splitting the bill

The Japanese word 割り勘 (わりかん) means "splitting the bill," "going Dutch," or "to share the cost." It refers to the practice of dividing the expenses among a group of people, typically after a meal, outing, or other shared activity. Each person pays their fair share of the total cost. This is a very common practice in Japan.

⚫︎ 今日の夕食は割り勘にしましょう。 Translation: Let's split the bill for dinner tonight. ⚫︎ 映画のチケット代は割り勘でした。 Translation: The movie ticket costs were split. ⚫︎ 飲み会はいつも割り勘です。 Translation: We always split the bill for drinking parties.

You use 割り勘 when you want to suggest or agree to split the cost of something. It is most frequently used among friends, colleagues, or casual acquaintances. You can use it at the beginning to suggest splitting the bill, or at the end of the outing when discussing how to pay. It’s also used when you are asked “How was the bill paid?”

割り勘 is typically written in hiragana as わりかん. The kanji version is 割勘, where 割 means "to divide, to split," and 勘 means "calculation" or "reckoning." However, it is far more common to see it written in hiragana. There is no variation in the okurigana.

There aren’t really perfect synonyms for 割り勘 because it is a very specific practice. However, related phrases could include: ⚫︎ 折半 (せっぱん) (literally "halving"): This implies exactly splitting the bill in half, often between two people. ⚫︎ 頭割り (あたまわり): This means "dividing by the number of heads," which is essentially the same as 割り勘.

The direct antonyms of 割り勘 would be concepts or phrases that mean "someone is paying" or "someone is treating." Some examples include: ⚫︎ 奢り (おごり) or 奢る (おごる): Treating someone, or to treat someone. ⚫︎ （誰々）のおごりです: It's (someone's) treat.

食事の後、会計の時に「割り勘でいいですか？」と聞きました。 ・Translation: After the meal, I asked "Shall we split the bill?" when it was time to pay. ・Explanation: This sentence demonstrates how to use 割り勘 to ask if everyone agrees to split the cost.

A：今日は私が全部払います。B：え、いいんですか？じゃあ、遠慮なく。 ・Translation: A: I'll pay for everything today. B: Really? Are you sure? In that case, I won't hesitate. ・Explanation: This conversation contrasts 割り勘 with someone treating the others.

The word 割り勘 is a compound word formed from 割 (わ), the stem of the verb 割る (わる), meaning "to divide" or "to split," and 勘定 (かんじょう), meaning "calculation," "bill," or "reckoning." Therefore, it literally means "dividing the bill" or "split reckoning".