What Is the Difference Between 이/가 and 은/는 in Korean?
Beginner Grammar Series
What Is the Difference Between 이/가 and 은/는 in Korean?
Learn attachment rules, subject focus, topic setting, contrast, sentence nuance, and the most common beginner mistakes.
When I first started learning Korean, I understood the attachment rules for 이/가 and 은/는, but I still chose the wrong particle in real conversations. The breakthrough came when I stopped translating them word for word and started listening for focus: was I identifying the subject, setting the topic, or creating contrast? That simple shift made Korean sentences feel much more logical.
Lesson Summary
- Use 이/가 to identify or emphasize the subject.
- Use 은/는 to set the topic or create contrast.
- Use 이/은 after a consonant and 가/는 after a vowel.
- New information often uses 이/가, while known topics often use 은/는.
- Context and emphasis matter more than direct English translation.
Quick Answer
이/가 marks and emphasizes the subject, especially for new information or answers to “who” and “what.” 은/는 sets the topic and is commonly used for contrast, general statements, and known information.
How These Korean Particles Work
Rather than translating each particle directly, ask what the speaker wants to highlight. 이/가 highlights the noun, while 은/는 frames that noun as the topic and often emphasizes what follows.
If you are learning Korean grammar, one topic almost certainly confuses you more than any other: understanding when to use 이/가 vs 은/는. Because English doesn't use attached postposition particles to mark grammatical roles, choosing between subject markers and topic markers can feel mysterious at first.
The secret is simple: both markers attach to nouns, but they signal completely different intentions in speech. In this ultimate beginner guide, we will break down the spelling rules for attaching each marker, explain the core functional differences between 이/가 vs 은/는, explore real sentence comparisons, highlight common mistakes, and test your skills with a practical quiz!
How do Korean particles attach to nouns?
Use 이 and 은 after nouns ending in a consonant, and 가 and 는 after nouns ending in a vowel.
Korean uses postpositional particles attached directly to the end of nouns to indicate their function in a sentence. Before choosing between a subject or topic marker, you must attach the correct form based on whether the preceding noun ends in a consonant (Batchim) or a vowel.
| Particle Type | Noun Ending in Consonant (Batchim) | Noun Ending in Vowel |
|---|---|---|
| Subject Marker (이/가) | Attach 이 (i) Ex: 선생님 + 이 → 선생님이 |
Attach 가 (ga) Ex: 친구 + 가 → 친구가 |
| Topic Marker (은/는) | Attach 은 (eun) Ex: 학생 + 은 → 학생은 |
Attach 는 (neun) Ex: 나 + 는 → 나는 |
When attaching 이 (i) or 은 (eun) to a noun with a final consonant (Batchim), the final consonant sound flows naturally into the vowel sound. For example, 책이 (book + is) is pronounced as 채기 (chae-gi).
When should you use 이/가?
Use 이/가 to identify or emphasize the grammatical subject, introduce new information, answer who or what questions, and with common patterns such as 있다, 없다, and 아니다.
The particles 이/가 (i/ga) identify the grammatical subject—the person or item performing the action or being described. Think of 이/가 as a spotlight shining directly on the noun itself.
Primary Functions of 이/가:
1. Introducing New Information:
Use 이/가 when introducing a subject into conversation for the very first time.
• 옛날에 한 남자가 살았습니다.
(A long time ago, a man [남자가] lived here.)
2. Answering "Who" or "What" (Emphasizing the Noun):
When answering questions like "Who did this?" or "What is good?", the answer focuses on the specific noun.
• Question: 누가 케이크를 먹었어요? (Who ate the cake?)
• Answer: 민수가 먹었어요. (Minsu [민수가] ate it.)
3. Fixed Grammar Patterns (있다/없다, 아니다, 좋다):
Certain verbs and adjectives mandatory pair with 이/가:
• Existence: 시간이 있어요. (I have time.)
• Non-existence: 돈이 없어요. (I don't have money.)
• Negative Identification: 저는 학생이 아니에요. (I am not a student.)
When should you use 은/는?
Use 은/는 to set the topic, introduce yourself, discuss known information, make general statements, or show contrast between two things.
The particles 은/는 (eun/neun) mark the topic of discussion—what the speaker is about to talk about. Rather than emphasizing the noun itself, 은/는 shifts focus to what happens next in the predicate (the rest of the sentence).
Primary Functions of 은/는:
1. Setting the Topic / "As for X...":
Use 은/는 to state what you are talking about or to state general facts.
• 저는 마이크입니다.
(As for me, I am Mike / My name is Mike.)
2. Showing Contrast or Comparison:
When comparing two items, 은/는 creates an "A is like this, BUT B is like that" nuance.
• 사과는 맛있어요. 하지만 바나나는 맛없어요.
(Apples are delicious. But bananas, on the other hand, are not.)
3. Repeating Known Information:
Once a topic has been introduced with 이/가, switch to 은/는 in subsequent sentences.
• First sentence: 새 차가 있어요. (I have a new car [introduced].)
• Next sentence: 그 차는 아주 빠라요. (As for that car [known topic], it is very fast.)
What is the main difference between 이/가 and 은/는?
이/가 places the focus on the noun itself, while 은/는 frames the noun as the topic and often shifts attention to the comment, action, or contrast that follows.
To master 이/가 vs 은/는, compare their core differences side-by-side in this summary table:
| Grammar Feature | Subject Marker (이/가) | Topic Marker (은/는) |
|---|---|---|
| Primary Focus | Shines spotlight on the NOUN itself. | Shines spotlight on the PREDICATE / ACTION. |
| Information Type | New information (unknown context). | Known topic / old information / general truth. |
| English Equivalent Nuance | "It is THIS SPECIFIC PERSON/THING that..." | "As for [X]..." / "Speaking of [X]..." |
| Special Functions | Used with 있다/없다, 아니다, Specific choice. | Used for contrasts, comparisons, and self-introductions. |
How does changing the particle change meaning?
Changing the particle can change the conversational emphasis. 날씨가 좋아요 simply identifies the weather as nice, while 날씨는 좋아요 can imply that the weather is nice but something else is not.
Notice how changing the particle drastically alters the conversational emphasis in these classic pairs:
Comparison 1: Weather Statement
• 날씨가 좋아요. (Nal-ssi-ga jo-a-yo.)
→ Focuses on the weather itself: "The weather is nice!" (Observing right now).
• 날씨는 좋아요. (Nal-ssi-neun jo-a-yo.)
→ Implies contrast: "The weather is nice (but maybe other things, like the food or hotel, are bad)."
Comparison 2: Identifying Someone
• 제가 했습니다. (Je-ga haess-seum-ni-da.)
→ Focus on identity: "I am the one who did it." (Answering 'Who did this?').
• 저는 했습니다. (Jeo-neun haess-seum-ni-da.)
→ Focus on contrast or action: "As for me, I did it (I don't know about the others)."
Common Mistakes to Avoid
- Do not assume 이/가 always means “subject” and 은/는 always means “topic” without considering emphasis.
- Do not use 은/는 automatically in every sentence about yourself.
- Remember that contrast can be implied even when the second item is not stated.
- Check whether the noun ends in a final consonant before choosing the particle form.
Real-World Sentence Comparisons
- 누가 왔어요? 민수가 왔어요. — 이/가 identifies the person who came.
- 저는 학생입니다. — 은/는 sets “me” as the topic.
- 커피는 마셔요. 차는 안 마셔요. — 은/는 creates contrast.
- 시간이 있어요. — 이/가 appears with 있다.
Quick Knowledge Check
Select the correct particle for each sentence based on grammar rules and context.
Question 1: Complete your self-introduction: "저[ ? ] 미국 사람입니다." (As for me, I am an American.)
A) 가 (ga)
B) 는 (neun)
C) 이 (i)
Question 2: Fill in the blank for fixed grammar: "시간[ ? ] 있어요?" (Do you have time?)
A) 이 (i)
B) 은 (eun)
C) 는 (neun)
Question 3: Someone asks: "누가 선생님이에요?" (Who is the teacher?). You point to Minjun and reply: "민준[ ? ] 선생님이에요."
A) 은 (eun)
B) 는 (neun)
C) 이 (i)
Question 4: Showing contrast: "커피[ ? ] 마셔요. 하지만 차[ ? ] 안 마셔요." (I drink coffee, but I don't drink tea.)
A) 는 / 는 (neun / neun)
B) 가 / 가 (ga / ga)
C) 이 / 가 (i / ga)
Show Answers
Answers:
1. B) 는 (neun) — 저는 is used for setting yourself as the discussion topic in self-introductions (저 ends in a vowel).
2. A) 이 (i) — The fixed verb 있다 takes the subject marker 이/가 (시간 ends in Batchim ㄴ).
3. C) 이 (i) — When answering "Who" (누가), use the subject marker 이/가 to emphasize the subject (민준 ends in Batchim ㄴ).
4. A) 는 / 는 (neun / neun) — Use the topic marker 은/는 to highlight contrast between coffee and tea.
Frequently Asked Questions
What is the main difference between 이/가 and 은/는?
이/가 marks the grammatical subject and emphasizes the noun itself, whereas 은/는 marks the topic of the sentence, emphasizing the information that follows or creating contrast.
Can I leave out particles like 이/가 or 은/는 when speaking Korean?
Yes! In casual everyday spoken Korean, native speakers frequently drop subject and topic particles when context makes the meaning obvious. However, including them is required in polite, formal, or written Korean.
Which particle should I use when introducing myself?
Always use 은/는 when introducing yourself! Say "저는 [Name]입니다" (As for me, I am [Name]) because you are setting yourself as the topic of conversation.
Why do we use 이/가 with 있다 and 없다?
In Korean grammar logic, items that exist or do not exist are treated as subject properties rather than direct object actions. Therefore, existence verbs like 있다 (to have/exist) and 없다 (to not have) require the subject marker 이/가.
How do I know if a noun ends in a consonant (Batchim)?
Look at the bottom of the final Korean syllable block. If there is a consonant letter sitting at the bottom (like ㄴ in 학생 or ㄱ in 책), it has a Batchim and takes 이 or 은.
Conclusion
Mastering 이/가 vs 은/는 is one of the biggest milestones in your Korean learning journey. Remember these simple principles: use 이/가 when you want to emphasize the subject noun, answer "Who/What", or use verbs like 있다/없다. Use 은/는 when stating topics, introducing yourself, or contrasting two different things. Keep practicing with real sentences, and choosing the right particle will soon become second nature!
