Affect vs. Effect – What’s the Difference?

Affect and effect are two of the most commonly confused words in English. They sound and look similar, and even relate in meaning — but they have different grammar functions and are used in different ways.

In this article, you’ll learn the difference between affect vs. effect, with grammar explanations, everyday examples, and simple tips to help you remember which one to use. By the end, you’ll feel confident using both in speaking and writing.

What Does “Affect” Mean?

Affect is most commonly used as a verb. It means “to influence” or “to change something.” When you affect something, you have an impact on it. This word is used when describing an action — usually one thing causing a change in another.

Examples:

• Weather can affect your mood.
• The loud noise affected my concentration.
• Lack of sleep affects how well you perform at work.

What Does “Effect” Mean?

Effect is most commonly used as a noun. It refers to the result or outcome of an action. An “effect” is what happens because of something else. If something affects you, the change you feel is the effect.

Examples:

• The new policy had a positive effect on the company.
• Stress can have serious health effects.
• The medicine had some side effects.

Difference Between “Affect” and “Effect”

The main difference between “affect” and “effect” lies in their part of speech and function in a sentence.

Affect is most commonly used as a verb. It means to influence, to change, or to have an impact on something. You use “affect” when describing an action that causes a result.

• The news affected everyone in the office.

Effect is most commonly used as a noun. It refers to the result, outcome, or consequence of an action. You use “effect” when describing what happened as a result of something else.

• The medicine had no side effects.

Quiz: Affect vs. Effect

1. The weather can strongly ____ your mood during the winter months.
a) affect
b) effect

2. The new law will go into ____ next month.
a) affect
b) effect

3. How will this decision ____ our final results?
a) affect
b) effect

4. The medicine had a few mild side ____, but nothing serious.
a) affect
b) effect

5. Negative feedback can sometimes deeply ____ a person’s confidence.
a) affect
b) effect

6. Lack of sleep has a direct ____ on your ability to concentrate.
a) affect
b) effect

7. His speech didn’t ____ the audience the way he expected.
a) affect
b) effect

8. Social media has a strong ____ on how people communicate today.
a) affect
b) effect

9. Will this change ____ your plans for the weekend?
a) affect
b) effect

10. The overall ____ of the presentation was very positive.
a) affect
b) effect

Quiz Answers

1) affect
2) effect
3) affect
4) effect
5) affect
6) effect
7) affect
8) effect
9) affect
10) effect