Side by side
은/는 vs 이/가: What's the Difference?
The question every learner keeps asking, from the first week to the intermediate level.
Both 은/는 and 이/가 can sit right after the same noun, and both often get translated into English as nothing at all. So 저는 학생이에요 and 제가 학생이에요 both come out as "I am a student", which makes it look like the choice doesn't matter.
It does. The two particles do completely different jobs. 은/는 tells the listener what you are talking about. 이/가 tells the listener which one specifically you mean.
In one line
은/는 sets the topic ('as for X...'). 이/가 identifies the subject ('it is X that...').
| Particle | Core meaning | Used with | Example |
|---|---|---|---|
| 은/는 (eun/neun) | Topic / Contrast | Known info, general truths, comparisons, self-introductions | 저는 학생이에요 jeoneun haksaengieyo As for me, I'm a student |
| 이/가 (i/ga) | Subject / Identification | New info, question words, 있다/없다, how something is right now | 누가 왔어요? nuga wasseoyo? Who came? |
When to Use 은/는
1. Setting the Topic
Use 은/는 to announce what the sentence is about. It works like saying 'as for...' in English. This is why almost every self-introduction starts with 저는.
저는 한국어를 공부해요.
jeoneun hangugeoreul gongbuhaeyo.
As for me, I study Korean.
2. Contrast
은/는 quietly implies that the statement is true for this thing, but maybe not for others. It draws a border around the topic.
커피는 좋아해요.
keopineun joahaeyo.
I like coffee (tea, maybe not).
3. General Truths & Known Info
Use 은/는 for definitions, facts, and anything the listener already knows about. Once a thing has been introduced, it becomes the topic.
고래는 포유류예요.
goraeneun poyuryuyeyo.
Whales are mammals.
When to Use 이/가
Use 이/가 when you are identifying or introducing the subject rather than commenting on a known topic. It points straight at the noun: this one, not the others. It is also the usual choice with question words, with 있다/없다, when you describe how something is right now (날씨가 좋아요), and inside subordinate clauses. General facts and contrasts still take 은/는: 겨울은 추워요 (winter is cold).
누가 전화했어요?
nuga jeonhwahaesseoyo?
Who called? (question word)
시간이 없어요.
sigani eopseoyo.
I don't have time. (with 없다)
날씨가 좋아요.
nalssiga joayo.
The weather is nice. (description)
The core difference
What you're talking about
“As for X...”
Which one you mean
“It is X that...”
Common mistakes
저가 했어요
jeoga haesseoyo
제가 했어요
jega haesseoyo
저 and 나 change shape before 가. 저+가 becomes 제가, 나+가 becomes 내가. Saying 저가 is an instant giveaway of a beginner.
누구가 왔어요?
nuguga wasseoyo?
누가 왔어요?
nuga wasseoyo?
누구 (who) also contracts before 가. It becomes 누가, never 누구가.
A: 누가 청소했어요? B: 저는 했어요.
A: nuga cheongsohaesseoyo? B: jeoneun haesseoyo.
A: 누가 청소했어요? B: 제가 했어요.
A: nuga cheongsohaesseoyo? B: jega haesseoyo.
The question asks WHICH person, so the answer must identify one. 저는 했어요 sounds like 'well, as for me, I did', dodging the question rather than answering it.
제가 마이클이에요. (introducing yourself)
jega maikeurieyo.
저는 마이클이에요.
jeoneun maikeurieyo.
A plain self-introduction sets a topic, so use 저는. 제가 마이클이에요 means 'I'm the one who is Michael', correct only if someone was looking for Michael.
저는 만든 음식
jeoneun mandeun eumsik
제가 만든 음식
jega mandeun eumsik
Inside a modifying clause ('the food that I made'), the subject takes 이/가, never 은/는. Topic particles only work in the main sentence.
저는 머리가 아파요
jeoneun meoriga apayo
Both particles, one sentence
This is correct Korean, not a mistake. 저는 is the topic ('as for me') and 머리가 is the subject ('the head hurts'). Korean sentences often carry both.
How to Choose in 5 Seconds
Ask these in order and stop at the first yes.
Frequently asked questions
Why is it 제가 and not 저가?
A few pronouns contract before the subject particle 가: 저 → 제가, 나 → 내가, 너 → 네가 (spoken 니가), and 누구 → 누가. With 은/는 there is no contraction, so 저는 and 나는 stay as they are.
Can one sentence use both particles?
Yes, and it's very common. 저는 머리가 아파요 ('as for me, my head hurts') has 저는 as the topic and 머리가 as the subject. Korean often stacks a topic and a subject in the same sentence.
Which one do I use to introduce myself?
Use 은/는: 저는 [name]이에요. Using 제가 would mean 'I am the one who is [name]', which only makes sense if someone was specifically looking for that person.
Why do question words always take 이/가?
Because a question word is asking you to identify something specific out of many options, which is exactly the job of 이/가. You cannot make an unknown thing the 'topic' of a sentence, so 누구는 왔어요? sounds odd. The exception is when you are contrasting people: 누구는 왔고 누구는 안 왔어요 ('some came and some didn't').
In a story, why does the particle change?
The first mention introduces new information, so it takes 이/가: 옛날에 왕이 살았어요 ('once there lived a king'). After that the king is known, so he becomes the topic: 그 왕은 아주 늙었어요 ('the king was very old').
Is 은/는 the same as the subject of the sentence?
Not necessarily. 은/는 marks the topic, which may or may not be the grammatical subject. In 그 책은 제가 읽었어요 ('as for that book, I read it'), the topic is the book but the subject is 제가.
Look them up in the dictionary
Both particles in the Basic Korean Dictionary from the National Institute of Korean Language, with English.