When do I need to use affect or when do I use effect?

Question

Affect is a verb and describes how one thing impacts another. For example: I was very affected by the President's speech.

Effect is a noun which describes a change which is a result or consequence of an action or other cause.

For example: The effects of the hurricane were seen for over 50 miles.

Effect and affect are often confused, so if you have difficulty remembering which is which, don't stress too much, it's quite a common mistake.

Answer 1

Most often, "effect" is a noun meaning a change resulting from a cause (in this sense we find the word in the term "sound effect"), and "affect" is a verb meaning to have an impact on something.

1. The effect of the rain was to create puddles in the street.
2. Talking during a point in a tennis match may affect the players' concentration.

These two meanings cover most day-to-day speech and writing.

Confusingly, however, "effect" can be a verb meaning "to take on something," often an attitude or piece of clothing or an accent:

1. He often effected an English accent as a joke.
2. He sometimes effected an attitude of detachment.

Finally, "affect" can be a noun meaning expressiveness or emotion.

His speech was monotone, lacking in affect.