Increase and Its Opposite: Simple Guide

If you are learning English, you already know that increase means to make something larger in amount, size, or degree. Its most direct and common opposite is decrease, which means to make something smaller. This guide will help you understand both words clearly, show you how to use them in real situations, and point out common mistakes so you can write and speak with confidence.

Quick Answer

Increase = to go up or become bigger. Decrease = to go down or become smaller. Use increase when talking about growth, rise, or addition. Use decrease when talking about reduction, drop, or subtraction. Both words can be verbs or nouns.

Understanding Increase and Decrease

These two words are direct antonyms. They are used in everyday conversation, business writing, academic work, and even casual emails. Knowing when to choose one over the other depends on what you want to say about change.

Increase as a Verb

When you use increase as a verb, you are describing an action that makes something larger. It is a regular verb: increase, increased, increased.

• Example: The company plans to increase its staff next year.
• Example: My daily water intake increased after I started exercising.

Decrease as a Verb

Decrease as a verb describes an action that makes something smaller. It is also regular: decrease, decreased, decreased.

• Example: We need to decrease our electricity usage this month.
• Example: The temperature decreased sharply overnight.

Increase and Decrease as Nouns

Both words can also be nouns. When used as nouns, they refer to the amount or fact of change.

• Example (increase as noun): There was a sudden increase in sales last quarter.
• Example (decrease as noun): A small decrease in speed can improve fuel efficiency.

Comparison Table: Increase vs. Decrease

Natural Examples in Context

Seeing these words in real sentences helps you understand how they work. Below are examples from different situations.

In Business Emails

• Increase: “We expect to increase our production capacity by 15% next month.”
• Decrease: “Please note that we must decrease our budget for office supplies.”

In Everyday Conversation

• Increase: “I need to increase the time I spend studying English.”
• Decrease: “The doctor told me to decrease my sugar intake.”

In Academic Writing

• Increase: “The study found a significant increase in test scores after the new method was used.”
• Decrease: “A decrease in pollution levels was observed over the five-year period.”

In News Headlines

• Increase: “Housing prices increase for the third straight month.”
• Decrease: “Unemployment rates decrease to a ten-year low.”

Formal vs. Informal Tone

Both increase and decrease are neutral words. They work in formal and informal settings. However, in very casual speech, native speakers sometimes use simpler words like go up or go down.

• Formal: “The committee voted to increase the membership fee.”
• Informal: “The price of gas went up again.”
• Formal: “We need to decrease operational costs.”
• Informal: “Let’s cut down on spending.”

If you are writing an email to a boss or a client, increase and decrease are safe and professional choices. In a text message to a friend, you can use the informal versions.

Common Mistakes

Even advanced learners sometimes make errors with these words. Here are the most frequent mistakes and how to fix them.

Mistake 1: Using the Wrong Preposition

Incorrect: “There was an increase on prices.”
Correct: “There was an increase in prices.”
Explanation: Use in after increase or decrease when talking about what changed. Do not use on or of in this pattern.

Mistake 2: Confusing Increase with Add

Incorrect: “Please increase sugar to the recipe.”
Correct: “Please add sugar to the recipe.”
Explanation: Increase means to make an existing amount larger. Add means to put something new in. If there is no sugar yet, you add it. If there is already some sugar, you increase the amount.

Mistake 3: Using Decrease When Reduce Is Better

Incorrect: “I want to decrease my weight.”
Correct: “I want to reduce my weight.”
Explanation: Both words are similar, but reduce is more common for personal goals like weight, stress, or time. Decrease is more common for numbers, statistics, or measurable data.

Mistake 4: Forgetting That Both Words Can Be Nouns

Incorrect: “There was a big increasing in sales.”
Correct: “There was a big increase in sales.”
Explanation: When you need a noun, use increase or decrease, not the gerund form increasing or decreasing.

Better Alternatives and When to Use Them

Sometimes you want a word that is more specific or has a slightly different tone. Here are some alternatives for increase and decrease.

Alternatives for Increase

• Rise – Use for natural or gradual upward movement. Example: “The sun rises early in summer.”
• Grow – Use for development over time. Example: “Her confidence grew after each lesson.”
• Boost – Use for a quick or intentional improvement. Example: “Drinking coffee can boost your energy.”
• Expand – Use for physical size or scope. Example: “The company plans to expand into new markets.”

Alternatives for Decrease

• Drop – Use for a sudden or sharp fall. Example: “Temperatures dropped below freezing.”
• Reduce – Use for intentional lowering. Example: “Please reduce the volume.”
• Lower – Use for adjusting a level. Example: “We need to lower our expectations.”
• Cut – Use for significant reduction, often in budgets or time. Example: “The manager decided to cut costs.”

When to Use Increase vs. Its Alternatives

If you are writing a formal report, increase is a safe choice. If you want to sound more natural in conversation, try go up or rise. For business emails, boost or expand can add energy to your message.

Mini Practice Section

Test your understanding with these four questions. Answers are below.

Question 1

Choose the correct word: “We saw a 10% _______ in sales this month.”
A) increase
B) increasing
C) increased

Question 2

Fill in the blank: “The doctor advised him to _______ his salt intake.”
A) increase
B) decrease
C) add

Question 3

Which sentence is correct?
A) “There was a decrease of temperature.”
B) “There was a decrease in temperature.”
C) “There was a decrease on temperature.”

Question 4

Choose the best word for a casual conversation: “The price of bread _______ again.”
A) increased
B) went up
C) rose

Answers

Answer 1: A) increase. The sentence needs a noun after “a 10%”.
Answer 2: B) decrease. The doctor wants him to consume less salt.
Answer 3: B) “There was a decrease in temperature.” Use in after decrease.
Answer 4: B) went up. In casual conversation, went up sounds most natural, though all three are grammatically correct.

Frequently Asked Questions

1. Can I use “increase” and “decrease” with percentages?

Yes. This is very common. For example: “Sales increased by 20%.” or “There was a 15% decrease in costs.” Always use by before the percentage when using the verb form.

2. What is the difference between “decrease” and “decline”?

Decrease is neutral and often used for numbers or measurable things. Decline can suggest a negative or gradual reduction, and it is also used for quality or health. Example: “His health declined.” (not “decreased”).

3. Is “increase” always positive?

No. While increase often sounds positive (like increase in profit), it can be negative too. For example: “There was an increase in crime.” The word itself is neutral; the context gives it a positive or negative meaning.

4. Can I use “increase” and “decrease” in the same sentence?

Yes. For example: “We want to increase productivity while we decrease waste.” This is a common and effective way to show contrast.

Final Tips for Learners

To master these words, practice using them in your own sentences. Write one sentence with increase and one with decrease every day for a week. Pay attention to the prepositions in and by. Listen for these words in news reports or business meetings. Over time, using them correctly will become automatic.

For more help with opposite words, explore our Beginner Vocabulary Pairs section. You can also find related guides in Common Opposites and Antonyms with Examples. If you have questions, visit our FAQ page or contact us.