What is the difference between "effect" and "affect"?

The words effect and affect are often confused because they sound similar. Do you know the difference?

Effect is a noun meaning "the result or outcome of a cause."

Affect is a verb meaning "to influence or alter."

A good way to remember the difference is that affect is the action.

Let's take a closer look at each in turn.

Effect is almost always a noun used to describe the result of an action. It is sometimes used as a verb that means to "cause to come into being," but this is not a common usage of the word. Some synonyms of effect are: result, outcome, aftermath, repercussion.

Examples of "effect":

• The effect on him was instantaneous.
• She used her powers to good effect.
• If we analyse the data, we can see the effect of the flash sale.

Affect is usually used as a verb meaning "to produce an effect" or "to cause or influence." Less frequently, the verb means "to put on a pretense." Occasionally, affect is used as a noun. It refers to someone's presentation of their mental state, and it is typically used by health professionals. Some synonyms of affect are: influence, upset, act on.

Examples of "affect":

• Will the accident affect her confidence?
• The bad weather may affect voter turnout.
• My brother gets hay fever, but pollen doesn't affect me.

Is the correct phrase "the effect of" or "the affect of"?

The right expression is "the effect of" – e.g. The effect of his strict manner was that she became shy around him.

What's the correct phrase, "to the effect that" or "to the affect that"?

The correct phrase is "to the effect that" – e.g. Sales had dropped to the effect that they were in danger of making a loss.

Which is right, "in effect" or "in affect"?

The right phrase is "in effect" – e.g. I have been training for the marathon for so long that, in effect, I feel like a professional athlete.

Should it be "does not affect the" or "does not effect the"?

The correct phrase is "does not affect the" – e.g. The choice of flavor does not affect the price of the product.

Is the correct phrase "likely to affect the" or "likely to effect the"?

You should use "likely to affect the" – e.g. Climate change is likely to affect the next generation worst of all.

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The definitions in this article were adapted from Wiktionary and Merriam-Webster.