뭐 and 무엇 both mean "what" in Korean. 뭐 is casual/spoken while 무엇 is formal/written.
Basic Forms
뭐 (Casual/Spoken)
Most common in conversation:
- 뭐예요? (What is it?)
- 뭐 해요? (What are you doing?)
- 뭐 먹어요? (What are you eating?)
무엇 (Formal/Written)
Used in formal situations:
- 무엇입니까? (What is it? - formal)
- 무엇을 원하십니까? (What do you want? - formal)
- 무엇이 필요합니까? (What is needed? - formal)
With Particles
Subject Particle: 뭐가/무엇이
What (as subject):
- 뭐가 좋아요? (What is good?)
- 뭐가 문제예요? (What's the problem?)
- 무엇이 필요합니까? (What is needed? - formal)
Object Particle: 뭘/무엇을
What (as object):
- 뭘 먹어요? (What are you eating?)
- 뭘 사고 싶어요? (What do you want to buy?)
- 무엇을 하십니까? (What are you doing? - formal)
Note: 뭐를 contracts to 뭘 in casual speech
Location: 뭐에
What...at/in/on:
- 뭐에 관심 있어요? (What are you interested in?)
- 뭐에 쓰여 있어요? (What is written on it?)
Means/Tool: 뭐로
What...with/by:
- 뭐로 갈까요? (What shall we go by?)
- 뭐로 쓸까요? (What shall we write with?)
- 뭐로 만들었어요? (What is it made from?)
Common Usage Patterns
Asking About Identity
What is something:
- 이게 뭐예요? (What is this?)
- 저게 뭐예요? (What is that?)
- 그게 뭐예요? (What is it?)
- 이름이 뭐예요? (What is [your] name?)
Asking About Actions
What someone is doing:
- 뭐 해요? (What are you doing?)
- 뭐 하고 있어요? (What are you doing now?)
- 뭐 했어요? (What did you do?)
- 뭐 할 거예요? (What will you do?)
Asking About Preferences
What someone wants/likes:
- 뭐 좋아해요? (What do you like?)
- 뭐 먹고 싶어요? (What do you want to eat?)
- 뭐 마실래요? (What do you want to drink?)
- 뭐 원해요? (What do you want?)
Asking for Clarification
When you didn't understand:
- 뭐라고요? (What did you say?)
- 뭐? (What? - very casual)
- 뭐예요? (What is it? / What?)
Common Expressions
Daily Questions
- 뭐 먹어요? (What are you eating?)
- 뭐 마셔요? (What are you drinking?)
- 뭐 봐요? (What are you watching?)
- 뭐 읽어요? (What are you reading?)
- 뭐 찾아요? (What are you looking for?)
Planning
- 뭐 할까요? (What shall we do?)
- 뭐 먹을까요? (What shall we eat?)
- 뭐 살까요? (What shall we buy?)
- 뭐 볼까요? (What shall we watch?)
Asking for Repetition
- 뭐라고 했어요? (What did you say?)
- 뭐라고요? (Pardon? / What did you say?)
- 뭐? (Huh? / What? - casual)
Compound Forms
뭐든지/무엇이든지 (Whatever)
Anything/whatever:
- 뭐든지 좋아요 (Anything is fine)
- 뭐든지 물어보세요 (Ask anything)
- 무엇이든지 도와드리겠습니다 (I'll help with whatever - formal)
뭔가/무언가 (Something)
Something (not specific):
- 뭔가 이상해요 (Something is strange)
- 뭔가 필요해요? (Do you need something?)
- 무언가 말씀하시겠습니까? (Would you like to say something? - formal)
뭐냐/무엇이냐 (What is - quoted)
In reported speech:
- 이게 뭐냐고 물었어요 (Asked what this is)
- 뭐냐고요? (What is it, you ask?)
Politeness Levels
Casual (반말)
- 뭐야? (What is it?)
- 뭐 해? (What are you doing?)
- 뭐 먹어? (What are you eating?)
Polite (해요체)
- 뭐예요? (What is it?)
- 뭐 해요? (What are you doing?)
- 뭐 먹어요? (What are you eating?)
Formal (합니다체)
- 무엇입니까? (What is it?)
- 무엇을 하십니까? (What are you doing?)
- 무엇을 드십니까? (What are you eating? - honorific)
Example Sentences
Basic Questions
- 이게 뭐예요? (What is this?)
- 지금 뭐 해요? (What are you doing now?)
- 점심에 뭐 먹었어요? (What did you eat for lunch?)
- 주말에 뭐 할 거예요? (What will you do on the weekend?)
Shopping
- 뭘 찾으세요? (What are you looking for?)
- 뭐가 필요하세요? (What do you need?)
- 뭘 드릴까요? (What shall I give you?)
At Restaurant
- 뭐 드시겠어요? (What would you like to eat?)
- 뭐 마시겠어요? (What would you like to drink?)
- 뭐가 맛있어요? (What's delicious?)
Example Dialogues
Dialogue 1: Meeting Someone
A: 이름이 뭐예요?
(What's your name?)
B: 민수예요. 당신은요?
(It's Minsu. And you?)
Dialogue 2: Making Plans
A: 주말에 뭐 할 거예요?
(What will you do on the weekend?)
B: 영화 볼 거예요. 같이 갈래요?
(I'm going to watch a movie. Want to go together?)
Dialogue 3: At Restaurant
A: 뭐 드시겠어요?
(What would you like to eat?)
B: 뭐가 맛있어요?
(What's delicious?)
A: 비빔밥이 인기가 많아요.
(Bibimbap is very popular.)
Dialogue 4: Didn't Hear
A: 내일 3시에 만나요.
(Let's meet at 3 tomorrow.)
B: 뭐라고요? 몇 시요?
(What did you say? What time?)
A: 3시요.
(3 o'clock.)
Common Mistakes
❌ Incorrect: 무엇해요?
No space/wrong combination
✅ Correct: 뭐 해요? or 무엇을 하십니까?
Casual with 뭐, formal needs particles
❌ Incorrect: 뭐을
Wrong contraction
✅ Correct: 뭘 (뭐를)
Proper contraction
❌ Incorrect: 뭐이에요?
Wrong particle
✅ Correct: 뭐예요?
뭐 + 예요
Usage Notes
When to Use 뭐 vs 무엇
Use 뭐:
- Casual conversation
- With friends/family
- Most everyday situations
- Spoken Korean
Use 무엇:
- Formal situations
- Written Korean
- Business/official contexts
- Very polite speech
Natural Contractions
In fast speech:
- 뭐 해요? → 뭐해요? (no space)
- 뭐를 → 뭘
- 뭐예요? (standard contraction from 무엇이에요)
Summary Table
| Form | Formality | Usage | Example |
|---|---|---|---|
| 뭐 | Casual | Spoken, everyday | 뭐 해요? |
| 무엇 | Formal | Written, formal | 무엇입니까? |
| 뭐가 | Casual | What (subject) | 뭐가 좋아요? |
| 뭘 | Casual | What (object) | 뭘 먹어요? |
| 뭐든지 | Any | Whatever | 뭐든지 좋아요 |
| 뭔가 | Any | Something | 뭔가 이상해요 |
Key Takeaways
- ✅ 뭐 = casual, 무엇 = formal: Choose based on situation
- ✅ 뭘 = 뭐를: Common contraction for object
- ✅ 뭐예요 most common: Standard question "what is it?"
- ✅ Takes particles: 뭐가, 뭘, 뭐로, 뭐에 etc.
- ✅ Very versatile: Use for identity, actions, preferences
- ✅ Essential question word: Must master for basic communication
뭐/무엇 is one of the most frequently used question words in Korean. Master both forms and their particle combinations to ask about anything naturally in any situation.