Korean grammar patterns › Level 4
-고 보니(까)
after doing …, (I realized / found that) …
Level 4 · TOPIK II · intermediate
How to use it
After completing an action, the speaker realized something they hadn't known before. Clause 2 is usually past, often with -더라고요 or -았/었네요.
Forming it
| 듣다 | → 듣고 보니 |
| 사다 | → 사고 보니까 |
| 오다 | → 오고 보니 |
Clause 1 is a completed action without a tense marker (✗ 들었고 보니).
Examples
설명을 듣고 보니 이해가 됐어요.
Once I heard the explanation, I understood.
집에 오고 보니 지갑을 식당에 두고 왔더라고요.
When I got home, I realized I'd left my wallet at the restaurant.
Compared with similar patterns
-다 보니(까) (G4-020) is about repeating/continuing an action over time; -고 보니 follows one completed action. -았/었더니 (G4-002) focuses on the result found; -고 보니 on the speaker's new realization.