-기 전에 and -(으)ㄴ 후에: Before and After in Korean

Quick answer: To say "before (doing something)" in Korean, attach -기 전에 (-gi jeone) to a plain verb stem: 먹기 전에 = before eating. To say "after (doing something)," attach -(으)ㄴ 후에 (-(eu)n hue) to the stem: 먹은 후에 = after eating. The "before" and "after" clause never carries a tense marker — the tense sits on the final verb of the sentence.

That last sentence is the whole lesson, and it's the part learners get wrong for years. In English, tense spreads everywhere: before I ate, after I had eaten, before I go. In Korean, the tense is marked exactly once, at the end. Everything before that is frozen.

The two forms

For -기 전에, take the dictionary form, drop 다, add 기 전에. There are no irregulars, no vowel choices, nothing. 가다 → 가기 전에. 먹다 → 먹기 전에. 만들다 → 만들기 전에. 듣다 → 듣기 전에. It is the easiest grammar point in Korean.

For -(으)ㄴ 후에, you add the past-tense modifier: stem ending in a vowel takes ㄴ, stem ending in a consonant takes 은. 가다 → 간 후에. 먹다 → 먹은 후에. Here the irregulars do show up: 만들다 → 만든 후에 (the ㄹ drops), 듣다 → 들은 후에, 돕다 → 도운 후에. If that shape looks familiar, it should — it's the same ending you meet in clauses that come before nouns. 후 is a noun meaning "after," so 먹은 후에 is literally "at the after of having eaten."

In real sentences

자기 전에 꼭 이를 닦아요. I always brush my teeth before I go to bed.

밥 먹기 전에 손을 씻으세요. Wash your hands before you eat.

한국에 오기 전에는 김치를 못 먹었어요. Before I came to Korea, I couldn't eat kimchi.

Look at that third one. In English, "came" is past. In Korean, 오기 is bare — the 었 lives only in 먹었어요. (The 는 on 전에는 is the topic marker adding a little contrast: before, as opposed to now.)

회의가 끝난 후에 전화할게요. I'll call you after the meeting ends.

운동한 후에 샤워했어요. I showered after working out.

졸업한 후에 뭐 할 거예요? What are you going to do after you graduate?

Same thing in reverse: 졸업한 looks past, but the sentence is about the future. 한 후에 is not "did" — it just means that action finishes first.

With nouns, you drop the verb machinery entirely and use 전에 / 후에 directly:

식사 후에 커피 한잔할까요? Shall we have a coffee after the meal?

세 시 전에 오실 수 있어요? Can you come before three o'clock?

10분 후에 다시 전화할게요. I'll call you back in ten minutes.

Note that 10분 후에 means "in ten minutes," and 10분 전에 in a past sentence means "ten minutes ago": 10분 전에 출발했어요 — They left ten minutes ago. Same word, and the tense of the main verb tells you which reading you get. If you want more ways to place things in time, see these Korean time words for later, earlier and now.

후에, 다음에, or 뒤에?

All three work after -(으)ㄴ, and all three are correct:

• 먹은 후에 — slightly bookish, very safe, common in writing and announcements
• 먹은 다음에 — the most common in casual speech
• 먹은 뒤에 — also common, feels neutral

In conversation a Korean friend is most likely to say 밥 먹은 다음에 갈게 (I'll go after I eat). In a sign or a pharmacist's instruction you'll see 식후 or 식사 후에. None of them is wrong in the other context — it's a lean, not a rule. The 에 is often dropped in writing: 30분 후 도착 (arriving in 30 minutes).

-(으)ㄴ 후에 vs just -고

This is the choice natives actually make. Compare:

손을 씻고 밥을 먹었어요. I washed my hands and ate.

손을 씻은 후에 밥을 먹었어요. I ate after washing my hands.

-고 strings two events together lightly: this, then that. -(으)ㄴ 후에 puts weight on the order — the first thing is finished, then the second begins. If someone asks you to do things in a specific sequence, 후에 is the natural choice. If you're just telling a story, -고 is lighter and more common. Overusing 후에 makes you sound like a set of instructions.

There's also -고 나서, which sits between the two: 숙제 다 하고 나서 놀아 — Finish your homework, then play. It emphasizes completion without the slightly formal feel of 후에.

Four mistakes to avoid

1. Putting tense in the 전에 clause. ❌ 밥을 먹었기 전에 → ✅ 밥을 먹기 전에 There is no such form as 먹었기 전에. Ever.

2. Using -는 or -(으)ㄴ before 전에. ❌ 가는 전에, ❌ 간 전에 → ✅ 가기 전에 전에 takes 기 and only 기.

3. Using 기 before 후에. ❌ 먹기 후에 → ✅ 먹은 후에 This is the single most common error. 전에 wants 기; 후에 wants -(으)ㄴ. Learn them as a mismatched pair, because that's exactly what they are.

4. Using 후에 to mean "later." ❌ 후에 봐요 → ✅ 나중에 봐요 / 이따가 봐요 후에 needs something to come after. On its own, "see you later" is 나중에 봐요 (later, unspecified) or 이따가 봐요 (later today). Similarly, standalone "before" in the sense of "previously" is 전에 by itself: 전에 한 번 가 봤어요 — I've been there once before.

One more thing about word order

Korean puts the time clause first, always. 밥을 먹은 후에 산책했어요, never *산책했어요 밥을 먹은 후에. English lets you flip it ("I took a walk after I ate"); Korean doesn't. If you're still getting the feel for where pieces go, this is a good moment to review how Korean sentence order works.

Also, the two clauses don't need the same subject:

친구가 오기 전에 방을 청소했어요. I cleaned my room before my friend came.

비가 오기 전에 빨래를 걷었어요. I took the laundry in before it rained.

FAQ

What is the difference between -기 전에 and -(으)ㄴ 후에 in Korean?

-기 전에 means "before doing X" and attaches to the plain verb stem with no changes (가기 전에, 먹기 전에). -(으)ㄴ 후에 means "after doing X" and attaches the past modifier -(으)ㄴ to the stem (간 후에, 먹은 후에). Neither clause takes a tense ending — the tense of the whole sentence goes on the final verb.

How do you say "before I sleep" in Korean?

자기 전에. 자다 (to sleep) drops 다 and takes 기 전에. A full sentence: 자기 전에 우유를 마셔요 — I drink milk before I go to bed. The same pattern gives you 나가기 전에 (before going out) and 먹기 전에 (before eating).

Should I say 후에 or 다음에?

Both are correct after -(으)ㄴ. In everyday speech 다음에 is more common — 밥 먹은 다음에 갈게요. 후에 sounds a touch more formal and shows up more in writing, instructions and announcements. 뒤에 also works and sits in between.

Practice

Fill in the blank or fix the sentence.

1. 한국에 (오다) ______ 한국어를 조금 배웠어요. (Before I came to Korea, I learned a little Korean.)
2. 영화가 (끝나다) ______ 같이 저녁 먹을까요? (Shall we eat dinner after the movie ends?)
3. Fix: 점심을 먹었기 전에 커피를 마셨어요.
4. Fix: 숙제를 하기 후에 쉬었어요.
5. Say in Korean: "I'll call you back in thirty minutes."

Answers

1. 오기 전에 — 한국에 오기 전에 한국어를 조금 배웠어요. (오기 전에는 also works, adding contrast.)

2. 끝난 후에 — 영화가 끝난 후에 같이 저녁 먹을까요? (끝난 다음에 is just as good, and more casual.)

3. 점심을 먹기 전에 커피를 마셨어요. The 전에 clause never takes 었.

4. 숙제를 한 후에 쉬었어요. 후에 needs -(으)ㄴ, not 기. (한 다음에 / 하고 나서 also work.)

5. 30분 후에 다시 전화할게요.