Affect and effect look and sound alike, and their meanings are related. That's exactly why they are so easy to confuse.

The short answer #

  • Affect is usually a verb: to influence something.
  • Effect is usually a noun: the result of a change.

The weather affects my mood. The weather has an effect on my mood.

Affect (verb) #

Use affect when something is doing the influencing.

  • Lack of sleep can affect your memory.
  • How will the new rule affect us?

Effect (noun) #

Use effect for the result or outcome. It often follows an, the, or an adjective.

  • The medicine had a strong effect.
  • What are the side effects?

A memory trick: RAVEN #

Remember: Affect is a Verb, Effect is a Noun.

The exceptions #

Both words have a less common second meaning:

  • Effect as a verb means to bring about: The new manager effected real change. (She made change happen.)
  • Affect as a noun is a psychology term for visible emotion: The patient had a flat affect.

In everyday writing, you'll almost always want affect for the action and effect for the result.

Common mistakes #

Wrong Right
The cold effected my voice. The cold affected my voice.
It had a big affect on sales. It had a big effect on sales.

Get it right every time #

AI Grammar Checker looks at how the word is used in your sentence and corrects affect and effect for you.