Affect vs. Effect: How to Use the Right Word Every Time

Examining Affect and Effect

Is it side effects or side affects? Take effect or take affect? Affect change or effect change?

Are you unsure about whether to use affect or effect? Do you find yourself simply guessing which of these words to use in a given sentence? You're not alone.

Why Is This Pair Commonly Confused?

Remembering the difference between affect and effect is especially confusing because both words have very similar pronunciations and meanings and can be used in verb or noun form. Even when affect or effect are used incorrectly in context, the writing can stil look gramatically correct.

Here's a sentence that uses both words correctly: "The cold weather affected the crops; the effect of the cold weather was a lower yield."

If you find yourself scratching your head unable to discern the difference between affect and effect in the above sentence, never fear! This article will explain when to use each word and provide examples to help you remember which word to use.

If you're curious to learn about other commonly confused words, check out Scribendi's Guide to Commonly Confused Words, which lists over 350 of these tricky terms.

The Quick Definitions: Affect or Effect?

Affect: Affect is a verb that means to influence something or, in relation to human behavior, to put on an act. As a noun, it has a definition specific to the field of psychology (a subjective emotion demonstrated through someone's actions).

Effect: Effect is a noun that means an outcome or result. It is also a verb that means "to make happen."

When to Use Affect

Affect is most commonly used in the transitive verb form (i.e., X affects Y). To affect something means that you are exerting an influence on it somehow—that is, you are changing it in some way. This usage of the word affect is pervasive in the English language and is synonymous with to have an effect on.

However, affect has another definition (also as a transitive verb): to put on a display or a pretense. This sense of the word pertains to deceptive human behavior, such as affecting (i.e., pretending) to like someone or affecting disinterest in something. It generally has negative connotations and is only rarely used this way (see the Merriam-Webster Dictionary's definitions of affect).

An even rarer use of the word affect is the noun form. In psychology, someone can demonstrate a particular affect, or a set of behaviors that can be observed, resulting from that individual's subjective emotions. Examples of this word include a blunted, constricted, flat, inappropriate, labile, or restricted affect (see The Free Dictionary's definition of "affect").

So, there are three situations where you can use the word affect. Use the verb if you are describing 1) something that is influencing something else, or 2) someone who is pretending to feel a certain way to manipulate their audience. Use the noun if you are talking about 3) the physical manifestation of a particular subjective behavior in a psychological context.

For example:

1) The book was starting to affect the way Bartholomew acted.

2) Bartholomew affected disinterest in the book, but the way he kept reading it day and night proved his fascination with the story.

3) If you ask me, a psychologist should observe Bartholomew's affect to see if there is cause for concern.

However, keep in mind that the first definition of affect—exerting an influence on something—is by far the most common.

The takeaway: If you're describing something or someone that has an influence on something or someone else, use affect. You might also need to use affect if you are describing an action someone takes based on a pretense (verb form) or an observable behavior arising from a subjective emotion (noun form).

When to Use Effect

Effect also has a noun form and a verb form.

Note that both the noun and verb forms of effect have a multitude of possible meanings. However, for simplicity, we'll focus on two main definitions.

The noun form of effect is much more common than the verb form. It means the outcome or result of some factor. For example, you have likely heard the phrase cause and effect, describing an interlinked chain of events.

There is also a verb form of this word: to effect something means to bring that thing about (i.e., to make it a reality). A common use of this verb is the phrase to effect change. As the Merriam-Webster Dictionary states, "the verb effect goes beyond mere influence; it refers to actual achievement of a final result."

So when do you use effect? 1) Use the noun if you are talking about a result of something, and 2) use the verb if you are talking about the process of generating an outcome.

For example:

1) Reading the book had a notable effect on Bartholomew's interactions with others.

2) It seemed to effect change in Bartholomew's social life, making him less and less inclined to seek human interaction, and more and more prone to reading in private.

The takeaway: If you're referring to a result of something, use effect. You can also use effect if you are describing an action where something or someone is causing a particular outcome.

How to Remember the Difference: Affect vs. Effect

Even though affect and effect have at least five definitions between them, you will primarily encounter only two of them: to affect (verb), which means to influence, and an effect (noun), which means an outcome or result. A handy trick to remember the difference between affect and effect is as follows:

An affect is an action.

An effect describes an eventuality or end result.

If you’re curious to learn more, check out some of our other featured articles, such as "Lay vs. Lie," "Who vs. Whom," and "Brake vs. Break," or ask one of our professional editors or proofreaders to review your writing. You'll see the positive effects in no time at all!

Common Phrases Using Affect or Effect

Take note of these common fixed expressions using affect or effect:

Affected tone: A pretentious or artificial way of speaking or writing; a tone that aims to sound sophisticated but comes across insincere
Flat affect: A lack of outward emotional expression
Take effect: To become operative
Sound effects: Sounds other than speech and music that accompany action or enhance realism in stage, video, and other broadcast productions
Side effects: Secondary and typically undesirable effects of a drug or medical treatment
Placebo effect: A phenomenon in which a patient's condition improves in response to treatment, not due to the specific treatment used but possibly due to the patient's belief in the treatment
Personal effects: Privately owned items, such as clothing and jewelry
Cause and effect: The direct relationship between an action or event and its consequence or result

Affect vs. Effect FAQ

Is effect ever a verb?

Yes. To effect something means to bring that thing about, or to make it a reality. A common use of this verb is the phrase to effect change. Use the verb form of effect when you are writing about generating an outcome.

Is affect ever a noun?

Yes. In psychology, someone can demonstrate a particular affect, or a set of behaviors resulting from their emotions. Examples of this word include a blunted, constricted, flat, inappropriate, labile, or restricted affect. Use the noun form of affect if you are writing about the physical manifestation of a particular subjective behavior in a psychological context.

How do I know whether to use affect or effect?

If you're describing something or someone that has an influence on something or someone else, use affect. You might also need to use affect if you are describing an action someone takes based on a pretense (verb form) or an observable behavior arising from a subjective emotion (noun form).

If you're referring to a result of something, use effect (noun form). You can also use effect if you are describing an action where something or someone is causing a particular outcome (verb form).

What is the fastest way to remember affect vs. effect?

These terms have several distinct meanings, but their most common uses are affect as a verb and effect as a verb. Here's a quick way to remember when to use affect vs. effect: an affect is an action; an effect describes an eventuality or end result.

Why is this pair commonly confused?

Affect and effect are commonly confused because they have highly similar spelling, pronunciation, and meaning. Incorrect uses of either term in context can still look grammatically correct. The common rules to use affect as a verb and effect as a noun are oversimplified, and fields such as psychology, economics, medicine, statistics, policy and business often use the trickier cases of these terms.

Affect vs. Effect: What's the Difference?