It's the age old dilemma. You're writing an email to a coworker and you stop in the middle of typing and have to ask yourself, "Is it affect or effect?"
These two words are tricky. They sound the same and they have similar meanings. They can even function as the same parts of speech. They’re like identical twins—they might seem almost alike at first glance, but once you get to know them, they’re not the same.
Even though you can both effect and affect change, the implications of that action vary. They might make grammatical sense when you change one out for the other, but you won’t have the same meaning once you do. Both words can each be one of two things—a verb or a noun. That’s right, you can’t use parts of speech to distinguish them. So what makes them different?
Let’s start with the noun version. By definition, effect as a noun means something that’s created. If your friend is surprised when you jump out at them wearing a mask, that action has the effect of scaring them. Effect as a noun can also mean something exists. If you say “that law is still in effect,” you’re saying that law still needs to be obeyed.
Affect as a noun is more abstract. Merriam-Webster notes that you usually find the noun form of affect in the psychology field. That’s because affect as a noun refers to a show of emotional expression. You could say someone has a dramatic affect (or none at all) when they’re surprised. The thing is, most people choose a different word for this context, so you’re not likely to encounter affect as a noun in everyday life.
The two get a little closer as verbs, but the actions they perform have different effects (see what I did there?).
To affect has a more tangible meaning—it refers to a material change or influence on an object or concept. You're not affected by a hurricane a thousand miles away, but you might be affected by your coworker quitting and leaving all their work to you.
To effect, on the other hand, is kind of like the end game of that influence. It refers to an accomplished goal or the cause for existence. You can say you want to effect change in the world someday—you want to create change as an end result. Instead of using effect as a verb, most of the time you’ll hear people say “create” or something similar.
It might seem confusing at first, but once you use affect and effect in different forms, you’ll be able to tell them apart easily. It might be helpful to remember that most of the time, affect is used as a verb and effect is generally a noun. There are exceptions, as noted above, but this is generally true for daily speech.