Good is an adjective, so it describes a noun or pronoun. Use good to talk about the quality of a person, thing, or situation. It answers “What kind?” or “How is it?” when the word being described is a noun.

Well is usually an adverb, so it describes a verb and tells how an action happens. Use well to talk about performance or the way something is done. It often answers “How?” about an action.

After linking verbs, English typically uses an adjective, not an adverb. With verbs like be, seem, look, feel, sound, taste, and smell, choose good when you are describing the subject. Choose well only when you truly mean health or when well is functioning as an adverb in a different structure.

Rule	Example
Use good after linking verbs to describe the subject	The soup tastes good.
Use well after linking verbs when you mean health	I feel well today.
Use well as an adverb to describe an action	She sings well.

Well can be an adjective meaning “in good health,” especially after feel, be, and get. Good does not mean “healthy” in standard usage, so “I am good” usually means your situation is fine or you are satisfied, not that your health is good. When talking about health, well is the clearer and more natural choice.

Rule	Example
Use well to mean healthy	He is well now.
Use good to mean fine or satisfactory	I’m good, thanks.
If you mean health, avoid I’m good as the only clue	I’m good, but I’m not feeling well.

Choose good or well based on what the question is asking you to describe. If the question is about a noun or a person’s condition, good may fit, and well fits when the condition is health. If the question is about an action, well is usually correct because it describes how the action happens.

Rule	Example
How was the movie	It was good.
How did you play	I played well.
How are you feeling	I feel well.

Some everyday phrases strongly prefer one word because of grammar and convention. Learning these patterns helps you sound natural and avoid hesitation. Focus on what is being described: a thing or state uses good, and an action uses well.

Word/Phrase	Definition	Example
good idea	high quality idea	That’s a good idea.
good job	praise for work done	Good job on the report.
do well	perform successfully	She did well on the test.
work well	function effectively	The plan works well.

With look and feel, you are often describing the subject, so good is common: “You look good,” “This feels good.” But if you mean health, well is possible with feel: “I feel well.” With look, well is uncommon for health in modern conversation and can sound formal or old-fashioned.

Rule	Example
Use good with look for appearance	You look good today.
Use good with feel for comfort or satisfaction	This chair feels good.
Use well with feel for health	I don’t feel well.

Good and well also have related forms that keep the same grammar pattern. Use better and best for comparisons with good or well depending on whether you need an adjective or an adverb. Well can also become the adjective better when it means health: “I’m better” is common for recovering.

Word/Phrase	Definition	Example
better	higher quality or improved performance	This one is better.
better	doing an action more effectively	She sings better now.
best	highest quality	That was the best part.
best	most effectively	He runs best in the morning.

In casual English, “I’m good” is a very common response meaning “I’m fine” or “No, thank you,” and most listeners accept it. In careful or formal contexts, “I’m well” is preferred when you are specifically talking about health. When you want to avoid ambiguity, add a clearer phrase like “I’m doing well” or “I’m feeling well.”

Rule	Example
Casual: I’m good can mean I’m fine	I’m good, thanks.
Formal or health-focused: prefer well	I’m well, thank you.
Clear performance: use doing well	I’m doing well at work.

To choose quickly, decide what word you are describing. If you describe a noun or the subject after a linking verb, use good. If you describe an action, use well. If you describe health, well is the standard choice.

Rule	Example
Describe a thing or person as a quality	It’s good.
Describe how an action happens	It went well.
Describe health	I’m not well.