Translation guide
The English verb "reduce" covers many meanings: making something smaller in size, amount, or intensity; lowering price or speed; simplifying; or even boiling down a liquid. Japanese uses different verbs depending on what is being reduced and how. This guide organizes the most useful equivalents by meaning.
To make something smaller in quantity, level, or intensity (e.g., reduce costs, reduce speed, reduce stress).
General verb for reducing quantity, number, or frequency. Often used for things like expenses, weight, or waste.
経費を減らす必要がある。
We need to reduce expenses.
ゴミを減らす努力をしよう。
Let's make an effort to reduce waste.
To lower something (price, volume, temperature, etc.). Often implies a deliberate action to bring something down.
値段を下げてもらえますか？
Could you reduce the price?
音量を下げてください。
Please reduce the volume.
Intransitive: to decrease, to become less. Use when the subject itself is reduced (e.g., population decreases).
人口が減っている。
The population is decreasing.
Formal term for cutting down or reducing, often used in business or policy contexts (budget cuts, staff reductions).
政府は予算を削減する計画だ。
The government plans to reduce the budget.
To suppress, keep down, or control (e.g., reduce speed, suppress emotions, keep costs low).
スピードを抑えて運転してください。
Please reduce your speed while driving.
To physically shrink something or make it more compact (e.g., reduce the size of a photo, reduce a swelling).
Literally "make small." The most straightforward way to say reduce in size.
写真を小さくして送ってください。
Please reduce the size of the photo and send it.
Formal term for scaling down, reducing in scale (e.g., reduce the scale of a project, reduce an image).
事業の規模を縮小する。
Reduce the scale of the business.
To compress (files, data) or reduce volume by pressure. Technical.
ファイルを圧縮して送ります。
I'll compress the file and send it.
To reduce something to its essential parts or a simpler state (e.g., reduce a problem to its core, reduce a fraction).
To reduce to a simpler form, often used in chemistry or logic. Also means 'return to original state'.
問題を根本に還元して考える。
Think by reducing the problem to its root.
Specifically for reducing fractions in mathematics.
分数を約分してください。
Please reduce the fraction.
To reduce a sauce or liquid by boiling to concentrate flavor.
To boil down, reduce by simmering. Common in cooking.
ソースを半分になるまで煮詰める。
Reduce the sauce until it is halved.
To reduce one's body weight.
To lose weight, become thin. Intransitive.
最近痩せたね。
You've reduced (lost weight) recently.
Transitive phrase: to reduce body weight.
体重を減らすために運動している。
I'm exercising to reduce my weight.
減らす is the most general 'reduce' for quantity/number. 下げる is for lowering something that has a level (price, volume, temperature). 削減する is formal and often used for budgets or staff cuts.
English 'reduce' can often be replaced by more specific verbs in Japanese. For example, 'reduce speed' is naturally スピードを落とす or 減速する, not just 減らす. Always consider what is being reduced.
二酸化炭素排出量を削減する必要がある。
We need to reduce our carbon footprint.
値段を少し下げてもらえますか？
Can you reduce the price a little?