-거든: If (Spoken Condition Before a Command)

There are two very different -거든 in Korean, and confusing them is one of the most common intermediate tangles. This page is about the connective -거든 — a colloquial "if / when" that links two clauses. It is not the sentence-final 거든(요) that means "you see / because," which lives among the discourse endings. Same three syllables, completely different grammar. We'll pull them apart carefully, because the difference is entirely about where the 거든 sits and what follows it.

The form: just stem + 거든

The good news about the form is that there's nothing to it. Connective -거든 attaches to any verb or adjective stem with no allomorphy — no 으 buffer, no vowel harmony, no ㄹ complications:

• 가다 → 가거든, 오다 → 오거든
• 먹다 → 먹거든, 있다 → 있거든
• 심심하다 → 심심하거든, 도착하다 → 도착하거든

Whatever the stem ends in, you simply add 거든. That's the whole rule.

The signature restriction: it sets up a command

Here is what makes connective -거든 special, and what you must internalize to use it correctly. The second clause is almost always an imperative, a request, or the speaker's own first-person resolve — an instruction, offer, or intention. It does not head a neutral declarative outcome the way -(으)면 does.

Think of -거든 as: "in the event that / whenever you happen to X — then do this." The whole construction leans forward into a directive.

Notice how at home -거든 is in directions and hospitality. "If you come to Seoul, be sure to…", "if you take that bus, get off at…" — this is its natural habitat: warm instructions for a future situation the listener may find themselves in.

The main clause can also be the speaker's own resolve (a first-person intention), or a proposal that includes the speaker:

Why you can't say "if it rains, the ground gets wet" with -거든

Because -거든 exists to set up a directive, it clashes with a neutral cause-and-effect statement. "비가 오거든 땅이 젖어요" ("if it rains, the ground gets wet") is odd precisely because 땅이 젖어요 is a plain observation, not an instruction. There's nothing for the "then do this" energy of -거든 to attach to. This is the single most important boundary to respect, and it's exactly where -거든 and -(으)면 diverge: -(으)면 heads any outcome, but -거든 heads a directive.

Register: warm, spoken, and a little old-fashioned

-거든 carries a distinct flavor. It is colloquial and warm, with a slightly folksy, even old-fashioned ring — the tone of an elder giving kindly advice, or a host's parting words ("if you're ever in the neighborhood, do drop by"). It is considerably less frequent than -(으)면, and in formal writing it's largely replaced by -(으)면. For that reason, most learners should aim to recognize -거든 reliably and reach for -(으)면 as their everyday default. When you do meet -거든 in a K-drama, a folk tale, or a warmly-worded set of directions, you'll now know exactly what it's doing.

Don't confuse it with the sentence-ender 거든(요)

The other -거든 — the one you'll hear far more often — sits at the very end of a sentence (usually with 요 attached) and means "you see / it's because / just so you know." It explains or justifies, and it does not link to a following clause:

Here 봤거든요 closes the sentence — it's giving a reason or a mild "for your information." That's the discourse ender, covered fully on its own 거든요 page. The way to keep them straight: connective -거든 is followed by another clause (a command); ender 거든(요) is followed by nothing — it ends the sentence. Position is everything.

Common Mistakes

Mistake 1: Pairing connective -거든 with a plain declarative outcome. The second clause must be a directive, not a neutral fact.

And if you do want -거든, make the second clause a command:

Mistake 2: Adding 요 to the connective 거든. The politeness 요 belongs on the sentence-final ender, never mid-sentence on the connective. Politeness on the whole utterance comes from the final verb (하세요).

Mistake 3: Using -거든 in formal writing. In a notice, email, or announcement, -거든 sounds too folksy; standard formal Korean uses -(으)면.

Mistake 4: Reading a sentence-final 거든요 as a condition. When 거든(요) closes the sentence, it's the "you see / because" ender — don't hunt for a missing "if."

Key Takeaways

• Connective -거든 attaches to any stem with no allomorphy: stem + 거든.
• Its second clause is a command, request, offer, or the speaker's own resolve — never a neutral declarative outcome (that's -(으)면).
• Its flavor is colloquial, warm, slightly old-fashioned, and it's much rarer than -(으)면 — recognize it, default to -(으)면.
• Keep it apart from the sentence-final 거든(요) ("you see / because"): connective -거든 is mid-sentence and followed by a command; the ender closes the sentence.