-고 있다 vs -아/어 있다: Progressive vs Resultant State

English says "I'm sitting" for two completely different situations: the moment you are lowering yourself into the chair, and the state of already being seated. Korean refuses to blur them. -고 있다 describes an action in progress; -아/어 있다 describes the state that remains after a change-of-state action has finished. Getting these two apart is one of the cleanest "aha" moments in Korean aspect, because once you see the split you can predict which one a native will use.

-고 있다: an action unfolding

-고 있다 attaches to a verb stem — completely unchanged, no vowel harmony — and means the action is currently underway. This is the pattern that lines up most neatly with the English progressive "be -ing."

Because -고 simply clips onto the stem, it is mechanically easy: 먹다 → 먹고 있다, 자다 → 자고 있다, 하다 → 하고 있다, 읽다 → 읽고 있다. There is no allomorphy to worry about. For the full treatment of the progressive, see -고 있다: the progressive.

-아/어 있다: the state left behind

-아/어 있다 means something different: the action is over, and what you are describing is the resulting state that persists. It follows vowel harmony, exactly like the past tense: ㅏ/ㅗ stems take 아, everything else takes 어.

In every case, the event (sitting down, standing up, snow falling, blooming) has already happened; -아/어 있다 reports the state that now holds. Compare this with the full page on -아/어 있다: resultant state.

The allomorphy

The decisive test: 가고 있다 vs 가 있다

The single sentence that makes the whole distinction click is the verb 가다 "to go." Put it in each pattern and you get two situations that are worlds apart:

가고 있다 = the going is in progress; you are still in transit. 가 있다 = the going is finished; you have arrived and remain there. English "I'm going" can't tell these apart, which is exactly why English speakers reach for the wrong one.

The same split shows up with posture verbs. 앉다 "to sit" gives you:

The transitivity restriction (this is the hard limit)

Here is the rule that saves you from the most common mistake: -아/어 있다 attaches only to intransitive, change-of-state verbs — verbs with no object, describing something that becomes a new state (오다, 가다, 앉다, 서다, 눕다, 피다, 남다, and passives like 닫히다). The instant a verb still takes a direct object, -아/어 있다 becomes impossible, and only -고 있다 is available.

You cannot say ×책을 읽어 있어요, because 읽다 "to read" is transitive — it still governs 책을. The logic is intuitive once you see it: -아/어 있다 describes a subject sitting in a resulting state, and a verb that is still doing something to an object has no such settled state to describe. This is also why passives fit so naturally: turning a transitive verb passive removes its object and gives you exactly the change-of-state verb that -아/어 있다 wants.

Notice 닫다 "to close" (transitive) → passive 닫히다 → 닫혀 있다 "is closed." The active 문을 닫고 있어요 means someone is in the act of closing the door; the passive 문이 닫혀 있어요 reports the result. See choosing between -고 있다 and -아 있다 for a decision-focused summary.

Common Mistakes

1. Using 가고 있다 to mean "I've arrived / I'm there." This is the flagship error. 가고 있다 keeps you moving; for "already there," you need 가 있다.

2. Forcing -아/어 있다 onto a transitive verb with an object. If the verb still takes 을/를, only -고 있다 works.

3. Using -고 있다 for a resting posture or result. For "is seated / is standing / is lying down," the state pattern -아/어 있다 is required; -고 있다 describes the transition, not the rest.

4. Botching the vowel contraction in -아/어 있다. 서다 + 어 contracts to 서 (two identical ㅓ merge), not 서어.

Key Takeaways

• -고 있다 = an action in progress (밥을 먹고 있다, 문을 닫고 있다); it clips onto any stem unchanged.
• -아/어 있다 = the state that persists after a change-of-state action (앉아 있다, 와 있다, 닫혀 있다); it follows vowel harmony.
• The clinching test: 가고 있다 "on the way (still moving)" vs 가 있다 "arrived and there."
• -아/어 있다 works only with intransitive / change-of-state verbs — never with a transitive verb that still takes an object (×책을 읽어 있다 → 책을 읽고 있다).