-(으)면: If / When

If you learn only one conditional in Korean, make it -(으)면. It is the neutral, default "if" — the ending you reach for unless you have a specific reason to use one of the specialized conditionals. What trips English speakers up is not the form (which is easy) but the range: a single Korean ending covers what English splits into "if" and "when." Once you see why Korean bundles those together, the ending becomes one of the most reliable tools in the language.

Building the form: 으면 or 면?

-(으)면 attaches to a verb or adjective stem, and the only choice you make is whether to insert 으:

• After a consonant 받침 (batchim), use 으면: 먹다 → 먹으면, 읽다 → 읽으면, 좋다 → 좋으면, 있다 → 있으면.
• After a vowel, use 면: 가다 → 가면, 오다 → 오면, 마시다 → 마시면.
• After a ㄹ stem, use 면 (the ㄹ stays; no 으): 살다 → 살면, 만들다 → 만들면.

The 으 is a "buffer vowel" that only appears when the stem ends in a consonant, so that 면 doesn't crash into it. This is the same 으 that surfaces in -(으)러 and countless other endings — see ㄹ-stem verbs for why ㄹ behaves like a vowel here and refuses the 으.

Notice 살면, not ×살으면 — a ㄹ stem never takes the 으.

The big idea: "if" and "when" are the same word

Here is the reframing that matters most. English keeps "if" (uncertain) and "when" (certain) apart. Korean does not. -(으)면 marks a clause as a condition — a situation whose fulfilment the main clause depends on — and it does not care whether that situation is uncertain, expected, or habitual. Context and the main-clause verb tell the listener which English word to reach for.

Real "if" — an open condition:

Habitual "when(ever)" — a recurring condition:

Temporal/future "when" — the trigger for a planned event:

All four sentences use the identical ending. English translates the first as "if," the last three as "when," but Korean sees one thing: situation A conditions event B.

What -(으)면 does NOT constrain

Unlike some of its cousins, -(으)면 is remarkably free:

• Subjects can differ. 네가 오면 나도 갈게요 — you come, I'll go. The two clauses need not share a subject.
• The main clause can be any mood. It can be a statement (꽃이 펴요), a request or command (연락해요), or a proposal (커피 한잔해요). This freedom is exactly what sets it apart from -거든, which demands a command.
• The 면-clause carries no future or 겠. Even when English says "if it will rain," Korean keeps the condition in the plain present: 비가 오면, never ×비가 올 거면 for a simple condition. The future/intention lives in the main clause.

Hypothetical "if": still just -(으)면

For a supposition about something unlikely or imagined, -(으)면 still works — the imagined flavor comes from the content, not a special ending:

When you want to foreground that you are entertaining a pure supposition — "supposing that…", "if I were…" — Korean offers the more vivid -(느)ㄴ다면. But you never need it: -(으)면 handles hypotheticals perfectly well and is the safer default.

Past 았/었으면: counterfactual wishes

There is one place where a past marker slips into the 면-clause: the wish frame 았/었으면 좋겠어요, literally "it would be good if [past] happened." The past here is not real past time — it signals that the situation is contrary to fact, a wish about how things aren't.

Read literally, 많았으면 좋겠어요 is "if [I] had had a lot, it would be good" — Korean reaches into the past-tense form to mark the gap between the wish and reality. This construction is common enough that learners should treat 았/었으면 좋겠어요 as a set expression for "I wish / I hope." (Contrast the plain present 많으면, which would just mean the open condition "if I have a lot.")

Common Mistakes

Mistake 1: Forgetting 으 after a consonant stem.

Mistake 2: Over-applying 으 to a ㄹ stem. The mirror-image error — a ㄹ stem already ends in a "vowel-like" consonant and rejects the 으.

Mistake 3: Translating habitual/future "when" with 때 instead of -(으)면. This is the classic transfer error. 도착할 때 means "at the moment of arriving" (a point in time you're inside of); for "once you arrive," you need the conditional.

Mistake 4: Using the past 았/었으면 for a real future condition. Plain 았/었으면 (without 좋겠다) reads as counterfactual. For a genuine "if you eat," keep the present.

Mistake 5: Cramming a future marker into the condition. English "if you will be late" becomes a plain-present condition in Korean.

Key Takeaways

• -(으)면 is the default conditional: reach for it first, and only switch to a specialized ending for a specific effect.
• Form: 으면 after a consonant, 면 after a vowel or ㄹ stem.
• One ending covers real "if," habitual/future "when(ever)," and hypothetical "if" — Korean does not split them the way English does. Future "when" is -(으)면, not 때.
• It is syntactically free: different subjects allowed, any main-clause mood allowed, no tense in the condition.
• 았/었으면 좋겠어요 is a set frame for counterfactual wishes ("I wish…"), the one place the past enters the 면-clause.