Collocation: Good in/at

Should you say "good at" or "good in"? Use "good at" for abilities, activities, tools and tasks. Use "good in" when you mean performance inside a setting, place, period or specific role.

Quick rule

Good at = skill, activity, tool, task. Good in = performance within a place, situation, time or role.

Good at: skills and activities (good at coding, good at chess, good at negotiation).
Good in: settings or contexts (good in a crisis, good in class, good in meetings).
If unsure, rephrase: use skilled/proficient + in/at or turn the noun into a verb phrase (good at + verb).

Core grammar (short and practical)

Ask yourself: Does the noun name what someone does (skill)? Or where/when they do it (setting)? If it's a skill → at. If it's a setting → in.

Answer to "What?": use good at.
Answer to "Where/When/Which setting?": use good in.

Skill: Right: I'm good at email triage.
Setting: Right: I'm good in fast-paced teams.

Common wrong → right pairs (copy these)

Frequent mistakes with ready-to-use corrections. Use them as templates.

Wrong: I'm good in tennis.
Right: I'm good at tennis.
Wrong: She's good in piano.
Right: She's good at the piano / She's good at playing the piano.
Wrong: He's good in programming.
Right: He's good at programming.
Wrong: They're good in math.
Right: They're good at math.
Wrong: I'm good in public speaking.
Right: I'm good at public speaking.
Wrong: He's good in chess.
Right: He's good at chess.
Wrong: She's good in chemistry.
Right: She's good at chemistry. (If you mean class performance: She's good in chemistry class.)
Wrong: I'm good in networking events.
Right: I'm good at networking / I'm good at meeting new people at events.
Wrong: He's good in negotiations.
Right: He's good at negotiating.
Wrong: We're good in the kitchen.
Right: We're good at cooking. (Keep "good in the kitchen" only if you mean the space.)

Work examples: copyable sentences for email, CV, meetings

At work, prefer "good at" for concrete capabilities and "good in" for how someone performs within roles or meetings.

CV: Skilled at project management (better than "good in project management").
Email: I'm good at synthesizing feedback into a clear plan.
Meeting: She's good in meetings - she brings people back to the objective.
Tool: He's good at Excel pivot tables.
Skill: I'm good at stakeholder communication and expectation-setting.
Role: They're good in client-facing roles; they keep conversations calm.

School examples: subjects, classes and exams

Use "good at" for subject ability; use "good in" for performance inside a class or exam.

Subject: She's good at chemistry (lab skills and understanding).
Class: She was good in chemistry class last year (performed well in that class).
Exam: He was good in the final exam (did well during the test).
Skill: They're good at essay writing for English literature.
Activity: I'm good at solving algebra problems.
Program: She's good in the honors program (handles the pace), and good at research methods (a skill).

Check your sentence

Test the whole sentence, not just the phrase. Context usually makes the right preposition obvious.

Casual speech: hobbies, parties and everyday talk

Same logic applies in informal contexts: hobbies and activities → at; settings and situations → in.

Hobby: I'm good at baking sourdough.
Setting: She's good in small groups - she starts interesting conversations.
Game: We're good at board games.
Party: He's good at hosting - great playlists and snacks.
Kitchen: Good at cooking (skill) vs good in the kitchen (comfortable working there).
Audience: She's good at performing live. "Good in front of a crowd" means she handles pressure well.

Rewrite help: fix your sentence in three quick steps

Three quick steps: 1) Identify whether the noun is an ability or a setting. 2) If ability → use at; if setting → use in. 3) If it still feels awkward, rephrase with skilled/proficient or make the noun a verb phrase.

Replace "good" with "skilled" or "proficient" - if that sounds natural, the matching preposition is probably right.
Turn a noun into a verb phrase: "good at playing the piano" is clearer than "good in piano."

Rewrite 1: Wrong: She is good in Spanish. →
Right: She is good at Spanish.
Alternative: She is proficient in Spanish.
Rewrite 2: Wrong: I'm good in coding. →
Right: I'm good at coding.
Alternative: I'm proficient in coding.
Rewrite 3: Wrong: He's good in presentations. →
Right: He's good at giving presentations.
Rewrite 4: Wrong: We're good in the kitchen. →
Right: We're good at cooking. (Keep "good in the kitchen" only if you mean the space.)
Rewrite 5: Wrong: She's good in client calls. →
Right: She's good at handling client calls. Or: She's good in client-facing roles.
Rewrite 6: Wrong: I'm good in sales. →
Right: I'm good at sales (skill). Or: I'm good in a sales role (performance in the role).

Memory tricks and fast checks

Quick micro-tests to use while proofreading or speaking:

Question test: Ask "What?" - if that answers the noun, use at. Ask "Where/When/Which?" - if that answers the noun, use in.
Swap test: Replace "good" with "skilled" (skilled at) or "effective" (effective in). If the swap feels natural, keep that preposition.
Hack example: What? → good at cooking. Where? → good in the kitchen. The meaning changes; choose the one you mean.

Similar mistakes, hyphenation and small grammar points

Watch similar collocations and small formatting rules.

Good with = able to handle people or things (She's good with children; he's good with deadlines).
Good for = beneficial (This exercise is good for your heart).
Proficient in is more formal and often used on CVs (proficient in Python ≈ good at Python).
Do not hyphenate: never write "good-at" or "good-in." Use a single space after the preposition.
Some fixed phrases vary by dialect and usage; context decides (e.g., "proficient in mathematics" is common even if "good at mathematics" is more idiomatic).

FAQ

Should I say 'good at English' or 'good in English'?

If you mean ability (speaking, reading, writing), say "good at English." Use "good in English" only when you refer to performance inside a class or exam: "She's good in English class."

Is 'good in math' acceptable?

"Good at math" is the usual idiomatic choice for ability. Use "good in math class" to refer specifically to class performance.

When is 'proficient in' better than 'good at'?

"Proficient in" is more formal and stronger - useful on CVs or technical descriptions (proficient in Python / proficient in Excel).

Can I avoid the problem by rephrasing?

Yes. Use "skilled at," "proficient in," or "good at" + verb (good at playing the piano). These options remove most preposition uncertainty.

How do I check many sentences quickly?

Scan using the What?/Where? test or replace "good" with "skilled/proficient" to see which preposition fits. A collocation-aware checker can also flag likely errors and suggest contextual corrections.

Quick practice

Try the three-step rewrite: identify skill vs setting, swap "skilled/proficient," or convert the noun to a verb phrase. Paste one sentence into the widget above to get a suggested correction.