How to say "ratio" in Japanese

• 比ひCommon
  noun, noun (suffix)The bare mathematical term for a ratio between two quantities, as in arithmetic or geometry. Outside mathematics it is seldom used alone; for proportions in everyday speech, 割合 is the natural choice.
• 率りつJLPT N3approx.Common
  noun, noun (suffix)Chiefly the word for 'rate': a quantity expressed as a proportion of a whole, typically as a percentage. It seldom stands alone, so for a plain mathematical ratio prefer 比 or 比率.
  実質じっしつ成長せいちょうと名目めいもく成長率せいちょうりつの差さは物価上昇ぶっかじょうしょうを意味いみする。↗

  Price increases explain the difference between the real and nominal growth rates.
• 割りわりCommon
  noun, noun (suffix)Seldom the word you want for plain 'ratio': it survives mainly in fixed expressions and compounds. For the everyday sense of proportion, use 割合.
• 割合わりあいJLPT N4approx.Common
  nounThe everyday word for the proportion of a whole: how much of a group or amount falls into a category, often expressible as a percentage. At home in both casual talk and formal explanation.
  クラスの女おんな生徒せいとの男おとこ生徒せいとに対たいする割合わりあいは３対たい２だ。↗

  The proportion of girls to boys in our class is three to two.
• 比率ひりつJLPT N1approx.Common
  nounThe technical term for a numerical ratio between two quantities, as in mathematics, statistics, or finance. Unlike 割合, it points to the calculated figure itself rather than a loose share of a whole.
  親おやに対たいする子こどもの比率ひりつが大おおきくなればなるほど子こどもを育そだてるのは難むずかしくなる。↗

  The higher the ratio of children to parents, the harder it is to bring up the children.

For a mathematical ratio between two quantities use 比 or, in technical contexts, 比率; for the proportion of a whole, often as a percentage, use 割合; 率 is chiefly for rates, and 「割り」 seldom stands alone.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 比ひratio
• 率りつrate
• 割りわりrate
• 割合わりあいrate
• 比率ひりつratio
• 歩合ぶあいrate
• 歩割ぶわりrate
• レシオratio
• プロポーションproportionate width
• 割り方わりかたrate