Good is an adjective and describes a noun. Well is an adverb and describes a verb. So you write a good cook but she cooks well. The rule breaks in one predictable place — after linking verbs like feel, taste and seem, where the adjective is correct and I feel good is perfectly standard English.

The basic rule

Ask what the word is describing. If it describes a person or thing, use good. If it describes an action, use well.

  • He is a good driver. — describes the driver.
  • He drives well. — describes the driving. Not he drives good.
  • That was a good presentation. — describes the presentation.
  • She presented well. — describes how she presented.

He drives good is common in casual American speech and is understood everywhere, but it is nonstandard in writing and will be marked as an error in academic or professional work.

The exception: linking verbs

Some verbs do not describe an action at all. They connect the subject to a description of it, and those verbs take an adjective — so good, not well.

The common linking verbs are be, seem, appear, become, and the sense verbs look, feel, sound, taste, smell.

  • The soup tastes good. — the soup is good, not the tasting.
  • That plan sounds good.
  • The proofs look good.

There is a quick test. If you can replace the verb with is and the sentence still makes sense, it is a linking verb and you want good. The soup is good works, so the soup tastes good is right.

Watch for verbs that go both ways. Smell is a linking verb in the bread smells good, but an action verb in the dog smells well — which would mean the dog has a fine sense of smell.

“Well” is also an adjective

This is the part that makes the pair genuinely confusing rather than merely fiddly. Well has a second life as an adjective meaning “not ill.” That is why both of these are correct, and why they do not mean the same thing:

Sentence What it means
I feel good. My mood or general state is positive.
I feel well. I am not sick.
You look good. You look attractive, or the outfit works.
You look well. You look healthy, especially after illness.
He isn’t doing good. Nonstandard, unless he has stopped charitable work.
He isn’t doing well. He is struggling — in health, business or school.

Older usage guides once insisted that I feel good was an error and that only I feel well was acceptable. That position has not survived. Both are standard now, and choosing between them is a matter of meaning rather than correctness.

“Did good” and “did well”

Did well means performed successfully. Did good means performed acts of charity or benefit — here good is a noun, not a misused adverb.

  • She did well on the certification exam.
  • The foundation has done a lot of good in the county.

The same noun sense sits behind do-gooder, for the greater good, and up to no good. When someone says you did good meaning you performed well, that is the nonstandard adverb use — fine in speech, out of place in writing.

Comparatives: both become “better”

Both words are irregular, and both share the same comparative and superlative forms:

  • good → better → best
  • well → better → best

There is no gooder, goodest, weller or wellest. Because better covers both, the adjective-adverb question disappears once you move up a degree: she writes better than I do and a better writer are both correct.

Hyphenating “well-“

A related rule that catches people out. Compounds beginning with well take a hyphen before the noun and drop it after the verb:

  • a well-known author — hyphenated, because it comes before the noun.
  • the author is well known — no hyphen.
  • a well-written report, but the report is well written.

Quick reference

Use… When
good Describing a noun: a good idea, good results.
good After a linking verb: it tastes good, that sounds good.
good As a noun: the greater good, do good.
well Describing a verb: she sings well, it went well.
well Meaning healthy: I’m well, she looks well.
better The comparative of both.

Common questions

Is “I’m good” correct?

Yes, in two ways. After the linking verb am, an adjective is expected, so it is grammatically sound. It also works as a conversational decline — Need a refill? No, I’m good — which is established American usage but too informal for professional writing.

Should I answer “How are you?” with “good” or “well”?

Both are correct. I’m well reports health; I’m good reports general state and is far more common in American speech. Neither is an error, despite the persistent belief that well is the only respectable answer.

Is it “played good” or “played well”?

Played well. Play is an action verb, so it takes an adverb. He played good is common in sports commentary and casual speech, but it is nonstandard in writing.

Which is right: “works good” or “works well”?

Works well. The one exception is when good is doing a different job in the sentence — it works good hours describes the hours, not the working.