Translation guide
The act of dividing something into two equal parts, or reducing something by half.
To split something into two halves of equal size, amount, or value.
The most common and versatile way to say 'to halve' or 'to divide in half'. Used for physical objects, quantities, and abstract things.
ケーキを半分にしてください。
Please halve the cake.
Let's split the profits in half.
Literally 'to divide into two equal parts'. More formal and precise than 半分にする. Often used in mathematical or technical contexts.
線分を二等分する点を求めなさい。
Find the point that bisects the line segment.
Specifically means to split costs or expenses equally between two parties. Common in financial or business contexts.
交通費は折半しましょう。
Let's split the travel expenses equally.
To decrease something to half of its original amount, size, or intensity.
Means 'to reduce by half'. Used for quantities, rates, time, etc. Often used in formal or written contexts.
生産コストを半減させる計画です。
It's a plan to halve production costs.
通勤時間が半減した。
My commuting time was cut in half.
A more casual, everyday way to say 'reduce by half'. Literally 'reduce to half'.
砂糖の量を半分に減らしたほうがいいよ。
You should halve the amount of sugar.
Intransitive: 'to become half'. Used when something is halved naturally or without specifying the agent.
この薬で痛みが半分になった。
This medicine halved the pain. (lit. The pain became half.)
半分にする is the general term for dividing something into two equal parts or reducing to half. 半減する specifically means reducing by half and is more formal. Use 半分にする for everyday situations and physical division; use 半減する for abstract reductions like costs, time, or rates.