Affect vs Effect: How to Choose the Right Word at Work

"Affect" and "effect" sound almost the same, look almost the same, and both relate to change. Native speakers mix them up too. In a work email, though, the wrong one can make an otherwise clear message look careless. The good news is that one simple test gets you the right word in nearly every business sentence.

The rule that covers most cases

Merriam-Webster sums it up this way: affect is usually a verb, and effect is usually a noun.

• Affect (verb): to act on or change someone or something. "The delay will affect the launch date."
• Effect (noun): a change that results when something is done or happens. "The delay had a big effect on the launch date."

Merriam-Webster's dictionary entry for affect connects the two in one line: something that affects a person has an effect on them.

A quick test you can use while typing

Look at the words right before the gap.

1. If you could put "the," "an," or an adjective in front of it, you need effect. "The effect," "an effect," "a strong effect," "side effects."
2. If it is doing the action in the sentence, you need affect. "This affects," "will affect," "did not affect," "was affected."

Another trick: try replacing the word with "influence" (a verb) or "result" (a noun). If "influence" fits, write affect. If "result" fits, write effect.

Before and after: common work sentences

Before: The new policy will effect all remote employees. After: The new policy will affect all remote employees. Why: "will ___ all remote employees" needs a verb meaning "change" or "influence."

Before: We are still measuring the affect of the price change. After: We are still measuring the effect of the price change. Why: "the ___ of" needs a noun. "The result of the price change" makes sense.

Before: The outage didn't effect our customers. After: The outage didn't affect our customers. Why: after "didn't," you need a verb.

Before: The changes will take affect on Monday. After: The changes will take effect on Monday. Why: "take effect" is a fixed phrase using the noun. Merriam-Webster's example is similar: "the law goes into effect next week."

Before: Sales were negatively effected by the holiday. After: Sales were negatively affected by the holiday. Why: "were ___ by" is a passive verb, so affected is right.

The exceptions, and when they matter

Merriam-Webster lists a few relatively uncommon exceptions. They are worth recognizing, mostly so they do not confuse you when you see them.

Effect as a verb. As a verb, effect generally means to cause something to come into being, or to accomplish it. Merriam-Webster's example: "the strike effected change within the company." Notice the difference:

• "The new manager affected the team's process." (The manager changed or influenced an existing process.)
• "The new manager effected a new process." (The manager brought a new process into existence.)

In business writing, "effect change" is the phrase you will meet most often. If you are not sure, a clearer verb is usually better: "The new manager introduced a new process" or "brought about change" says the same thing with no risk of confusion.

Affect as a noun. Merriam-Webster notes that the noun affect is used mainly in psychology, for an observable emotional response, as in "The patient had a flat affect." You will almost never need this in a work email.

Affect meaning "pretend." The dictionary also lists a second verb sense: to put on a false appearance of something. Its example is "He affected a French accent." This sense is uncommon in business writing, but it explains why you may see affected used to mean "not natural" or "put on."

A table to keep nearby

You want to say	Word	Example
to change or influence	affect	Rain may affect attendance.
a result or impact	effect	Rain had no effect on attendance.
to start applying	take effect / go into effect	The rule takes effect in May.
to bring about	effect (formal)	The board effected several changes.
emotional expression (psychology)	affect (noun)	rare in business writing

Key takeaways

• In almost every business sentence, affect is the verb (to change or influence) and effect is the noun (the result).
• If "the," "an," or an adjective fits in front, use effect; if the word is the action, use affect.
• "Take effect" and "go into effect" are fixed phrases that use the noun effect.
• Effect as a verb means to bring something about, as in "effect change"; use a plainer verb if you are unsure.
• The noun affect belongs mainly to psychology and rarely appears in work emails.