Good is an adjective, so it describes a noun: a good book, good coffee, good news. Well is an adverb, so it describes a verb — how something is done: she sings well, the car runs well, you did well. The rule of thumb: you do a good job, but you do the job well. There are two twists to remember — after linking verbs like taste, look, and seem you use good ("it tastes good"), and well can also be an adjective when it means "in good health" ("I feel well").
An adjective modifies a noun or pronoun. Good tells you something about a person, place, or thing:
If you can point to the noun the word is describing, "good" is almost always what you want. It does not describe a verb — that is the adverb's job.
An adverb modifies a verb, an adjective, or another adverb. Well usually tells you how an action is performed:
It can also modify an adjective or participle — which is why we talk about a well-written report, a well-known author, or a well-behaved dog. Whenever the word is pinned to an action or describes how something was done, well is the safe choice.
This is where most mistakes happen. Linking verbs — be, seem, look, feel, taste, smell, sound, appear, become — do not describe an action. They connect the subject to a word that describes the subject. Because that word describes a noun, it must be an adjective, so you use good, not "well":
This is exactly why "I feel good" is correct English, no matter what a strict-sounding friend tells you. "Feel" is a linking verb, and "good" describes you, the subject. James Brown had it right in "I Got You (I Feel Good)."
Action verbs need "well":
Nouns and linking verbs need "good":
Here is the exception to the "well = adverb" rule: well is also an adjective when it refers to health. This is the one time "well" describes a noun rather than a verb:
So "I feel well" is about your health, while "I feel good" is about your mood or general state. Both are correct; they just answer slightly different questions.
All three are correct, but they are not identical:
Watch this pair closely:
Swap in bad or badly. They mirror good and well perfectly: "bad" is the adjective, "badly" is the adverb. Say the sentence with the "b" word, use whichever sounds right, then match it:
If badly fits, use well. If bad fits, use good.
The core grammar is identical on both sides of the Atlantic: British and American English follow the same adjective/adverb rule, and both use "well" for health. The only real difference is social, not grammatical. The reply "I'm good" (meaning "I'm fine, thanks") spread from American English and is now common everywhere, but some British speakers — and prescriptivists in both countries — still prefer "I'm well" or "I'm very well, thank you" in polite or formal settings. It's a matter of register, not right versus wrong.
In formal English, no — you're describing how you're doing, which is an action, so use the adverb: "I'm doing well." Taken literally, "I'm doing good" means you're performing good deeds. That said, "I'm good" is perfectly fine in casual speech as a way to say you're fine or content.
Both are correct, but they mean different things. "I feel good" describes your mood or overall state — you're happy, positive, upbeat. "I feel well" specifically means you're in good health. After the linking verb "feel," both act as adjectives, so choose based on whether you mean happy (good) or healthy (well).
Only when "good" is a noun meaning good deeds — as in "the volunteers did good in their neighborhood." If you mean someone performed well, on a test or in a match, the correct form is "did well," because "well" is the adverb describing the action. Casual speech blurs this, but formal writing keeps "did well."
"Good" is an adjective: it describes nouns, as in "a good book" or "good news." "Well" is an adverb: it describes verbs and how actions happen, as in "she writes well." The two exceptions are linking verbs, which take "good" ("it smells good"), and health, where "well" works as an adjective ("I feel well").
In standard English, no. Use "well" for adverbs: "he drives well," not "he drives good." Using "good" as an adverb — "runs good," "played good" — is common in casual and regional speech but is considered nonstandard in formal writing. The safe rule: if the word modifies a verb, choose "well."
