These two words look alike and often sound alike, but they do different jobs.
- Affect is usually a verb: to change or influence something.
- Effect is usually a noun: the result of that change.
Affect: the action
To affect something means to have an influence on it.
The rain affected our plans for the weekend.
Lack of sleep can affect your concentration.
You will often see it in the passive:
Thousands of people were affected by the storm.
Effect: the result
An effect is what happens because of something.
The rain had a big effect on our plans.
One side effect of the medicine is feeling tired.
Easy way to remember it
Think A for Action and E for End result.
- The action happens first: something affects you.
- The end result comes after: you feel the effect.
Another popular trick is the word RAVEN:
Remember, Affect is a Verb, Effect is a Noun.
Common mistakes
Need a verb? Use affect.
❌ The noise effected my sleep.
✅ The noise affected my sleep.
Need a noun? Use effect.
❌ The noise had a bad affect on my sleep.
✅ The noise had a bad effect on my sleep.
A quick test: if you can put a, an or the in front of it, you almost certainly need effect.
Useful phrases with effect
- have an effect on something: Music has a calming effect on me.
- side effect: an extra, usually unwanted result, especially of medicine.
- take effect: start to work. The new rules take effect in January.
- in effect: in practice, or currently valid. The ban is still in effect.
Notice that it is have an effect on, not have an effect to.
The rare exceptions
Just starting out? You can safely skip this part.
- Effect can be a formal verb meaning to make happen: The new manager effected real change.
- Affect can be a noun in psychology, meaning the emotion someone shows.
In everyday English, the simple rule always works: affect is the verb, effect is the noun.