The distinction between 은/는 (topic marker) and 이/가 (subject marker) is one of the most challenging aspects of Korean for learners. While both can translate to the subject in English, they serve fundamentally different functions.
Core Difference
은/는 (Topic Marker)
- Marks what the sentence is about
- Establishes context or theme
- Often implies contrast
- "As for...", "speaking of..."
이/가 (Subject Marker)
- Marks who/what does the action
- Identifies the grammatical subject
- Provides new information
- Emphasis on the actor/entity
Visual Comparison
| Aspect | 은/는 | 이/가 |
|---|---|---|
| Function | Topic of discussion | Grammatical subject |
| Information | Known/given | New/focus |
| Emphasis | Context, contrast | Actor, doer |
| Scope | Broader statement | Specific subject |
| Translation | "As for...", "speaking of..." | Direct subject |
When to Use 은/는
1. General Statements
Making broad observations or universal truths:
- 사과는 과일이에요. (Apples are fruit.)
- 겨울은 추워요. (Winter is cold.)
- 한국은 아시아에 있어요. (Korea is in Asia.)
2. Self-Introduction
Always use 은/는 for introducing yourself:
- 저는 학생이에요. (I'm a student.)
- 제 이름은 수진이에요. (My name is Sujin.)
- 저는 서울에 살아요. (I live in Seoul.)
3. Known Information
When topic is already established or assumed:
A: 친구를 만났어요? (Did you meet your friend?) B: 네, 친구는 집에 있었어요. (Yes, as for the friend, they were at home.)
4. Contrast
Implying or explicitly stating contrast:
- 저는 커피를 좋아해요. (I like coffee.) [but maybe you don't]
- 오늘은 바빠요. 내일은 시간이 있어요. (Today I'm busy. Tomorrow I have time.)
When to Use 이/가
1. Answering "Who/What"
Responding to questions about identity:
Q: 누가 왔어요? (Who came?) A: 친구가 왔어요. (My friend came.)
Q: 뭐가 필요해요? (What's needed?) A: 펜이 필요해요. (A pen is needed.)
2. New Information
Introducing something not previously mentioned:
- 비가 와요. (It's raining.) - First mention of rain
- 사람이 왔어요. (A person came.) - New person entering scene
3. Neutral Observations
Objective descriptions without contrast:
- 날씨가 좋아요. (The weather is good.)
- 꽃이 예뻐요. (The flower is pretty.)
- 음식이 맛있어요. (The food is delicious.)
4. Existential Sentences
With 있다/없다:
- 시간이 있어요. (There's time.)
- 책이 없어요. (There's no book.)
5. Emphasis on Subject
Stressing who specifically did something:
- 제가 했어요. (It was ME who did it.)
- 누나가 만들었어요. (It was sister who made it.)
Side-by-Side Examples
Example 1: Weather
이/가 (Neutral observation):
- 비가 와요. (It's raining.)
- Simple factual statement
은/는 (Contrast):
- 비는 와요. (As for rain, it's coming.)
- Implies: "Rain is falling, but maybe sunshine isn't"
Example 2: Introduction
은/는 (Self-introduction - CORRECT):
- 저는 학생이에요. (I'm a student.)
이/가 (Wrong for introduction):
- 제가 학생이에요. (It's ME who's a student.)
- Sounds like emphasis/correction, not introduction
Example 3: Description
이/가 (Neutral description):
- 방이 커요. (The room is big.)
- Simple observation
은/는 (Contrast implied):
- 방은 커요. (As for the room, it's big.)
- Implies: "The room is big, but maybe other parts aren't"
Example 4: Answering Questions
Question: 누가 왔어요? (Who came?)
Correct: 친구가 왔어요. (Friend came.) - 이/가 for new info Wrong: 친구는 왔어요. (Sounds contrastive: "Friend came [but someone else didn't]")
Double Particle Sentences
Korean frequently uses both particles in one sentence:
[Topic + 은/는] + [Subject + 이/가] + [Predicate]
This structure describes a characteristic or possession of the topic:
-
저는 시간이 없어요. (I don't have time.)
- 저는 = topic (me)
- 시간이 = subject (time)
- Literally: "As for me, time doesn't exist"
-
친구는 키가 커요. (My friend is tall.)
- 친구는 = topic (friend)
- 키가 = subject (height)
- Literally: "As for my friend, height is tall"
-
한국은 음식이 맛있어요. (Korea has delicious food.)
- 한국은 = topic (Korea)
- 음식이 = subject (food)
- Literally: "As for Korea, food is delicious"
The Contrast Nuance of 은/는
은/는 often carries implicit contrast, even when not stated:
Implicit contrast:
- 저는 학생이에요. (I'm a student.) [you might not be]
- 이것은 좋아요. (This is good.) [that might not be]
- 오늘은 바빠요. (Today I'm busy.) [other days I'm not]
Explicit contrast:
- 저는 커피를 좋아하지만 친구는 차를 좋아해요.
- (I like coffee, but my friend likes tea.)
With Existential Verbs
이/가 (Neutral existence)
- 책이 있어요. (There is a book.)
- 시간이 없어요. (There's no time.)
은/는 (Contrast)
- 책은 있어요. (As for books, I have some.) [but not other things]
- 시간은 없어요. (As for time, I don't have any.) [but I have other things]
Example dialogue: Q: 펜이 있어요? (Do you have a pen?) A: 펜은 없어요. 연필은 있어요. (As for pens no, but as for pencils yes.)
Common Mistakes
Mistake 1: Using 이/가 for Self-Introduction
❌ 제가 학생이에요. ✅ 저는 학생이에요.
Self-introductions always use 은/는.
Mistake 2: Using 은/는 to Answer "Who"
Q: 누가 왔어요? (Who came?) ❌ 친구는 왔어요. (Sounds contrastive) ✅ 친구가 왔어요. (Friend came.)
New information answering "who/what" needs 이/가.
Mistake 3: Confusing Topic and Subject
Not understanding that 은/는 marks what you're talking about, while 이/가 marks the grammatical actor.
Practical Guidelines
Use 은/는 when:
✅ Introducing yourself ✅ Making general statements ✅ Topic is known/established ✅ Contrasting with something else ✅ Providing your opinion/preference
Use 이/가 when:
✅ Answering "who" or "what" ✅ Introducing new information ✅ Making neutral observations ✅ Using 있다/없다 ✅ Emphasizing the subject ✅ Natural phenomena (rain, snow)
Question Words Always Take 이/가
Always 이/가, never 은/는:
- 누가 왔어요? (Who came?)
- 뭐가 있어요? (What's there?)
- 어디가 아파요? (Where hurts?)
- 언제가 좋아요? (When is good?)
Topic-Comment Structure
Korean is fundamentally a topic-comment language:
English (Subject-Predicate):
- I am a student. (Subject-Verb-Complement)
Korean (Topic-Comment):
- 저는 학생이에요. (As for me, [I'm] a student.)
This structure doesn't exist in English, which is why the distinction is challenging. Korean establishes a topic (은/는), then comments about it.
When Both Are Possible
Sometimes either can be used with different nuances:
날씨가 좋아요. (Weather is good.) - Neutral observation 날씨는 좋아요. (As for the weather, it's good.) - Slight contrast implied
비가 와요. (It's raining.) - Simple statement 비는 와요. (As for rain, it's coming.) - Contrast: rain yes, but maybe not other weather
Context determines which sounds more natural.
Key Takeaways
- ✅ 은/는 = Topic (what sentence is about)
- ✅ 이/가 = Subject (who/what acts)
- ✅ 은/는 often implies contrast
- ✅ 이/가 introduces new information ✅ Both can appear in one sentence ✅ Self-introduction always uses 은/는 ✅ Answering "who/what" always uses 이/가 ✅ Question words always take 이/가
Understanding this distinction takes time and exposure to natural Korean. Pay attention to usage patterns in Korean content, and with practice, choosing the right particle becomes intuitive.