Effect is a noun that means ‘result, consequence of change’ – e.g. cause and effect. Affect is a verb that means ‘influence, make a difference to’ – e.g. The accident affected her health. We confuse the spellings of these words because their pronunciation and meanings are very close. Simple rule: Effect (End result) vs. Affect (Action).
This is the easiest rule to remember the difference between effect (noun) and affect (verb).
Ask yourself: Is it an end result (noun) or is it an action (verb)?
You will choose the correct word 99% of the time if you follow this rule. However, there are rare situations when affect can be used as a noun and when effect can be used as a verb (we will look at this later in ‘Exceptions’).
In many situations, we can choose to use effect (noun) or affect (verb) to express the same thing. To do this, we need to change the sentence construction. Both words can be used in past, present and future tenses, and to express a positive or negative.
| Time | Effect (noun) | Affect (verb) |
| Past | The accident had an effect on her health. | The accident affected her health. |
| Present | What are the effects of this medicine? | How does this medicine affect the patient? |
| Future | We will all feel the effect of climate change. | Climate change will affect us all. |
Effect (noun) means: ‘the result of a specific influence or change’.
Synonyms: result, consequence, outcome, end result, fallout, impact.
Set expressions: come into effect, have an effect on/upon, take effect, in effect, for effect.
Additional meanings: Special effects are visual and audio features in a movie that make a stage scene appear like real life. Effects can also be used in a formal situation to mean ‘someone’s personal possessions’.
Examples with effect (noun) in a sentence:
Affect (verb) means: ‘to influence or cause a change’.
Synonyms: alter, change, influence, modify, disturb, impact upon.
Set expressions: be affected by (something/someone).
Additional meanings: Affect can also formally mean ‘to pretend or imitate’ as in: She affected a northern accent.
Examples with affect (verb) in a sentence:
As we mentioned earlier, it is possible for effect to be used as a verb and for affect to be used as a noun. This is rare in English, but it is important that we understand this usage so that we do not make mistakes when spelling these words.
As a verb, effect means: ‘to bring into existence or put into operation.’
For example: The Prime Minister is determined to effect the will of the people.
As a noun, affect refers to: ‘a display of emotion via facial, vocal, physical expressions.‘
This is only used in a medical (psychology / psychiatry) context and is very rare in English.
For example: The depressed patient presented with a melancholy affect. (The patient appeared to be sad)
Try these exercises to test your understanding of the differences between effect and affect. There are a couple at the end that deal with ‘exceptions to the rule’ so watch out for these!
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