Background -는데 / -(으)ㄴ데

What it means

-는데 sets the scene. You give some background first ("I'm eating now..."), then say your main point ("do you want to join me?"). It can also show contrast, like "but", or make a sentence softer and less direct. In English we often use "and", "but", "so" or just a pause (...) for this.

How to make it

• Action verbs → 는데: 가다 → 가는데, 먹다 → 먹는데
• 있다/없다 and words ending in them → 는데: 재미있다 → 재미있는데, 맛없다 → 맛없는데
• Adjectives ending in a vowel → ㄴ데: 바쁘다 → 바쁜데, 예쁘다 → 예쁜데
• Adjectives ending in a consonant → 은데: 작다 → 작은데, 많다 → 많은데
• ㄹ stems drop the ㄹ: 살다 → 사는데, 길다 → 긴데
• Nouns → 인데: 학생 → 학생인데, 친구 → 친구인데
• Past tense, for every word type → 았/었는데: 가다 → 갔는데, 바쁘다 → 바빴는데

When to use it

• Background, then a question or suggestion: 지금 밥 먹는데 같이 먹을래요? (I'm eating now — do you want to eat together?)
• Contrast ("but"): 이 가방은 예쁜데 너무 비싸요. (This bag is pretty, but it's too expensive.)
• Starting a story: 어제 시장에 갔는데 사람이 정말 많았어요. (I went to the market yesterday, and there were so many people.)
• Softening at the end of a sentence with -는데요: 저는 학생인데요. (Well, I'm a student...) It politely leaves room for the other person to respond.

Compare

• -지만 = a clear "but": 예쁘지만 비싸요. (It's pretty, but it's expensive.)
• -는데 = softer. It can mean "but", or just give background: 예쁜데 비싸요. (It's pretty, but... it's expensive.)

Common mistakes

• ❌ 예쁘는데 → ✅ 예쁜데 (adjectives use -(으)ㄴ데)
• ❌ 재미있은데 → ✅ 재미있는데 (있다/없다 words use -는데)
• ❌ 어제 시장에 가는데 → ✅ 어제 시장에 갔는데 (a finished past action needs 았/었는데)