Translation guide
The English word "decrease" can be expressed in Japanese through verbs, nouns, and descriptive phrases. The most common and versatile option is 減る (heru) for intransitive use and 減らす (herasu) for transitive use. Other words like 減少する (genshō suru) are more formal, while 下がる (sagaru) is used for drops in level or value. This guide organizes expressions by the type of decrease and the grammatical role needed.
To say that something decreases by itself (e.g., population, sales, weight).
The most common and versatile intransitive verb for a decrease in quantity, number, or amount. Used in everyday speech.
A formal, written-style verb often used in reports, news, and statistics. It is a suru-verb.
売上が大幅に減少した。
Sales decreased significantly.
Used for a decrease in quality, standard, ability, or level. Often formal.
品質が低下している。
The quality is decreasing.
To say that someone or something decreases something else (e.g., reduce costs, cut staff).
The most common transitive verb meaning to reduce or decrease something. Used in daily conversation.
To express that a numerical value, price, temperature, or rank goes down.
To say that something becomes weaker, less intense, or diminishes.
To use "decrease" as a noun in a sentence.
減る (heru) is for a decrease in quantity or number, while 下がる (sagaru) is for a decrease in level, value, or position. For example, 体重が減る (weight decreases) vs. 気温が下がる (temperature decreases).
English often uses 'decrease' as both noun and verb, but Japanese requires choosing the right word based on what is decreasing and whether it is transitive or intransitive. Using 減少する for everything can sound overly formal in casual speech.
経費を減らす必要がある。
We need to decrease expenses.
砂糖の量を減らしてください。
Please reduce the amount of sugar.
Formal term for cutting down or reducing, often used for budgets, costs, or personnel.
政府は予算を削減した。
The government decreased the budget.
Intransitive verb for something going down. Very common for prices, temperature, grades, etc.
気温が下がった。
The temperature decreased.
物価が下がっている。
Prices are decreasing.
Transitive verb for lowering something. Used for prices, volume, rank, etc.
店は値段を下げた。
The store decreased the prices.
Formal term for a drop, especially in stock prices or market values.
株価が急激に下落した。
Stock prices decreased sharply.
Intransitive verb meaning to weaken or abate. Used for wind, rain, force, etc.
風が弱まった。
The wind decreased (in strength).
To decline in vigor, health, or power. Often used for people, abilities, or influence.
体力が衰えてきた。
My physical strength has decreased.
The standard noun for decrease or reduction. Can be used with する to form a verb.
人口の減少が問題だ。
The decrease in population is a problem.
Noun for a drop or decline in quality, level, or ability.
品質の低下が著しい。
The decrease in quality is remarkable.