-(으)러: To (Purpose of Going/Coming)

-(으)러 answers one very specific question: why did you go there? It is the "in order to" of errands and trips — "I went to the store to buy milk," "I'm going to Korea to study." It's one of the first purpose forms Korean learners meet, and it's genuinely easy, but it comes with one hard restriction that makes it different from every other purpose ending: the main clause must be a verb of motion. Miss that, and even a perfectly natural-sounding sentence will be wrong.

Building the form: 으러 or 러?

-(으)러 attaches to a verb stem, with the familiar 으 buffer:

• After a consonant 받침, use 으러: 먹다 → 먹으러, 읽다 → 읽으러, 찾다 → 찾으러.
• After a vowel, use 러: 배우다 → 배우러, 보다 → 보러, 만나다 → 만나러.
• After a ㄹ stem, use 러 (the ㄹ stays, no 으): 만들다 → 만들러, 놀다 → 놀러.

The defining restriction: the main verb must be motion

Here is the rule that governs everything about -(으)러: the main clause has to be a verb of motion — 가다 (go), 오다 (come), 다니다 (go regularly/attend), and their motion compounds like 나가다 (go out), 들어오다 (come in), 올라가다 (go up). The -(으)러 clause states the purpose of that movement.

Every one of these has a movement verb in the main clause — 다녀요, 왔어요, 나갔어요, 가요 — and -(으)러 tells you the reason for the trip. This is why the pattern feels so tightly bound to errands: the whole construction is movement toward a goal.

One subtlety clears up a lot of confusion: it is the main verb that must be motion — the purpose verb on -(으)러 can be anything at all, including 사다 (buy).

Here 사다 (buy) is the purpose and 나갔다 오다 (go out and come back) is the motion main verb — perfectly fine. The error is only when 사다 becomes the main verb, as in ×우유 사러 준비했어요: the purpose is fine, but 준비하다 (prepare) isn't motion.

Two more constraints: same subject, no tense on 러

Beyond the motion rule, -(으)러 has two quiet constraints that keep it simple:

Same subject. The person doing the purpose action and the person moving are one and the same. In 밥을 먹으러 식당에 가요, I both eat and go. -(으)러 cannot bridge two different subjects.

No tense on the ending. -(으)러 itself never carries past or future — it stays bare. All the tense lives on the motion verb. "I went to eat" puts the past on 갔어요, not on 먹으러:

The purpose clause 보러 stays tenseless; 갔어요 carries the "yesterday." This is a general trait of Korean connective endings — tense typically sits on the final verb — but it's especially clean with -(으)러 because the ending has no allomorph for tense at all.

Asking and answering the purpose

Because -(으)러 is about purpose, it sits at the heart of the everyday question "what did you come/go there to do?" — 뭐 하러…? Koreans ask and answer purpose with this frame constantly:

The answer simply drops the specific purpose (책을 빌리러) into the same slot 하러 held in the question. One nuance worth knowing: 뭐 하러 also has a colloquial, rhetorical life meaning "why on earth / what for" — 뭐 하러 그런 걸 사요? ("what did you buy that for?") — the same words with a dismissive edge.

The boundary with -(으)려고

The mirror-image ending -(으)려고 also means "in order to," and the two are constantly confused. The distinction is exactly the motion rule: -(으)러 needs a motion main verb; -(으)려고 does not. So when the purpose leads to buying, preparing, or studying — anything non-motion — only -(으)려고 works:

You cannot say ×공부하러 책을 샀어요, because 사다 (buy) is not motion. The full side-by-side is on the -(으)러 vs -(으)려고 page; for now, hold onto the reflex: no movement, no -(으)러.

Common Mistakes

Mistake 1: Pairing -(으)러 with a non-motion main verb. The most frequent error by far. Buying, preparing, and studying are not movement.

Mistake 2: Attaching -(으)러 to a non-motion "do" pattern. "I try/intend to exercise" has no motion verb at all — it needs -(으)려고 하다.

Mistake 3: Dropping the 으 after a consonant stem.

Mistake 4: Putting tense on -(으)러. Tense belongs on the motion verb, not the purpose clause.

Key Takeaways

• -(으)러 expresses the purpose of a movement: "go/come somewhere in order to do X." It answers "why did you go there?"
• Form: 으러 after a consonant, 러 after a vowel or ㄹ stem.
• The main clause must be a motion verb — 가다, 오다, 다니다, or a motion compound. No motion, no -(으)러.
• Same subject in both clauses, and no tense on 러 — the tense sits on the motion verb.
• For purpose with a non-motion main verb, switch to -(으)려고.