Key difference: The main difference between “affect” and “effect,” is the fact that in most cases “affect” is used as a verb, whereas, “effect” is used as a noun. “Affect” means to have an influence on something. “Effect,” on the other hand, denotes a result, it is a consequence.

The main difference between “affect” and “effect,” is the fact that in most cases “affect” is used as a verb, whereas, “effect” is used as a noun. “Affect” means to have an influence on something. For example: The rain affected the clothes; as in the rain made the clothes wet. “Effect,” on the other hand, denotes a result, it is a consequence. For example: The rain had an effect on the clothes and it wasn’t pleasant; the effect was that the clothes were wet.

A way to distinguish this is that “affect” is a verb; hence it is from the subject’s point of view. The rain affected the clothes; as in the rain made the clothes wet. It is from the point of view of the rain; the rain made the clothes wet. “Effect,” as a noun is usually from the objects point of view. The rain had an effect on the clothes and it wasn’t pleasant; the effect was that the clothes were wet. This is from the point of view of the clothes; sthe clothes got wet because of the rain.

Dictionary.com defines ‘affect’ as:

• To act on; produce an effect or change in: Cold weather affected the crops.
• To impress the mind or move the feelings of: The music affected him deeply.

Dictionary.com defines ‘effect’ as:

• Something that is produced by an agency or cause; result; consequence: Exposure to the sun had the effect of toughening his skin.
• Power to produce results; efficacy; force; validity; influence: His protest had no effect.
• The state of being effective or operative; operation or execution; accomplishment or fulfillment: to bring a plan into effect.
• A mental or emotional impression produced, as by a painting or a speech.
• Meaning or sense; purpose or intention: She disapproved of the proposal and wrote to that effect.
• The making of a desired impression: We had the feeling that the big, expensive car was only for effect.
• An illusory phenomenon: a three-dimensional effect.
• A real phenomenon (usually named for its discoverer): the Doppler effect.
• Special effects.

Another way to distinguish is so check the word’s synonyms. If the synonyms fit in to the sentence, then the use of ‘affect’ and ‘effect’ is probably correct.

Synonyms of ‘affect’:

To act on, to move, influence, sway, modify, alter, touch, stir, change, disturb, induce, involve, transform, simulate, take on.

Examples of ‘affect’:

• Rain affected the crops.           
• Her love affected him deeply.
• Exposure to the sunlight affects the eyes.
• The new government affects the poor the most.
• The new iPhone affected the sales of other products.
• Inflation affects the buying power of the currency.
• The ending of the Titanic affected her deeply.

Synonyms of ‘effect’:

Result, consequence, reaction, outcome, issue, something produced by an action or a cause, aftereffect, aftermath, backlash, backwash, chain reaction, conclusion, development, end product, event.

Examples of ‘effect’:

• Mary’s decision had no effect on John.
• It is time to put our diabolical plan into effect.
• The new attendance policy had no effect on the employees.
• The drug had an immediate effect on the pain.
• The government's action had no effect on the trade imbalance.
• A new regulation goes into effect tomorrow.
• The beneficial effects of exercise are well documented.
• Corporations need to think about the long-term effects of their actions.
• The lighting effects emphasized the harsh atmosphere of the drama.
• The movie had great visual effects.

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