은/는 vs 이/가: Korean Topic and Subject Particles

Students mix these up because the English looks the same. "I am a student" can be 저는 학생이에요 or 제가 학생이에요, and both are real Korean. They are not interchangeable. 은/는 says what you are talking about. 이/가 points at the noun that is the news.

The other particles, including 을/를 and 도, are in Korean particles explained. This page stays on the choice between these two.

The same English, two Korean sentences

If you walk into a class and introduce yourself, use 저는. If the teacher asks 누가 학생이에요? and you are answering, use 제가.

Which spelling to pick

Each pair has two spellings. Look at the last syllable of the noun. A final consonant is a batchim. No batchim means the syllable ends in a vowel.

• Consonant: 책 takes 은 and 이. 책은, 책이.
• Vowel: 커피 and 날씨 take 는 and 가. 커피는, 날씨가.

저 is a vowel too, so the topic form is 저는. A few common words do not simply add 가. Learn these as a set:

• 저 + 가 → 제가 (I, polite)
• 나 + 가 → 내가 (I, with friends)
• 누구 + 가 → 누가 (who)
• 뭐 + 가 → 뭐가 (what, as the subject)

은/는 sets the topic

은/는 means "as for this." It also marks a contrast, the thing that is different from something else.

저 is polite. With friends, 나 replaces it: 나는 학생이야. In fast speech 나는 becomes 난. The ending 이야 is casual. Polite 이에요 and 예요 are covered in polite speech.

이/가 brings the news

Use 이/가 when the noun is the new piece of information: the answer to who or what, the thing that exists, or the thing in some state.

Both in one sentence

Korean often sets a topic and then puts 이/가 on a different noun.

A useful check: if you can add "as for" in English, you are looking at 은/는. If you are answering who or what, you are looking at 이/가. Weather, existence (있어요, 없어요), and who or what questions lean toward 가. Introductions and contrasts lean toward 는.

What people actually say

In casual talk both particles drop when everyone already knows the point. 나 학생이야 is a normal way to say you are a student with a friend. 누구 왔어? is a normal "who came?"

Write the particles anyway while you are learning. Dropping 는 can also drop a contrast you meant. 커피는 마셔요 says something about coffee as against other drinks. 커피 마셔요 just says you drink coffee.

Mistakes to fix early

• Using 제가 for a plain introduction. 제가 학생이에요 answers who the student is. The hello-my-name line is 저는.
• Writing 저가, 나가, or 누구가. The correct forms are 제가, 내가, and 누가, in speech and in writing.
• Choosing from the romanization. 커피 looks like it ends in a consonant in English. In Hangul it ends in a vowel, so 커피는.
• Putting 은/는 on the thing 아니에요 denies. 학생이 아니에요, with 이.

Check yourself

은/는 and 이/가: quick answers

Practice in Hanuri

Foundations keeps this choice short, then asks you to pick the particle. After this pair feels steady, 에 vs 에서 is the next one students mix up.