-고 있다 vs -아/어 있다

Rules of thumb

• Action in progress: -고 있다, with both transitive and intransitive verbs (밥을 먹고 있어요 'I'm eating').
• Resulting state: -아/어 있다, only with intransitive or passive verbs (앉아 있다 'be seated', 열려 있다 'be open', 서 있다 'be standing').
• -아/어 있다 does not work with transitive verbs that take an object (* 문을 열어 있다).
• Wearing verbs (입다, 신다, 쓰다, 끼다) use -고 있다 for the state of wearing (안경을 쓰고 있어요 'She's wearing glasses').
• 앉고 있어요 = in the middle of sitting down; 앉아 있어요 = is sitting (state).

Example sentences

Your browser has no Korean voice installed, so audio can't be played.

• 동생은 지금 방에서 숙제를 하고 있어요.-고 있다

  My younger brother is doing his homework in his room.

• 창문이 열려 있어요.-아/어 있다

  The window is open.

• 창문을 열어 있어요.

  Incorrect

  The window is open. [Wrong: 'open' here is transitive; -a/eo itda needs the passive verb 'be opened']

• 할머니께서 의자에 앉아 계세요.-아/어 있다

  Grandma is sitting on the chair.

• 그 사람은 빨간 코트를 입고 있어요.-고 있다

  That person is wearing a red coat.

Often confused with

• -아/어 있다 vs -아/어 놓다, -아/어 두다