In short

This lesson adds the three “purpose” tools that go beyond the spoken -(으)러 / -(으)려고 of lesson 31. Use -기 위해서 for a formal, written in order to: 합격하기 위해서 공부해요 (hapgyeokhagi wihaeseo gongbuhaeyo, I study in order to pass). Use -도록 for a purpose aimed at someone/something else, for a negative purpose, and for to the extent that: 늦지 않도록 일찍 나갔어요 (neutji antorok iljjik nagasseoyo, I left early so as not to be late). Use -(으)려면 for if you intend to X, then (do) Y: 한국어를 잘하려면 매일 연습하세요 (hangugeoreul jalharyeomyeon maeil yeonseuphaseyo, to get good at Korean, practice every day).

The rule

Step 1 - -기 위해서 = the formal “in order to”

Nominalize the verb with -기 (lesson 36) and add 위해서 (from the verb 위하다, to do for the sake of, to aim at):

Verb stem + -기 위해서 + main clause -> 살을 빼기 위해 운동해요. (sareul ppaegi wihae undonghaeyo) - I exercise to lose weight.

• 위해서 freely shortens to 위해 (wihae); the very formal, written variant is 위하여 (wihayeo). All three mean the same.
• For a plain noun goal, use N + 을/를 위해서: 건강을 위해서 (geongangeul wihaeseo, for one’s health), 가족을 위해서 (gajogeul wihaeseo, for one’s family).
• When the “for” phrase modifies a following noun, 위해서 must become the adnominal 위한: 건강을 위한 운동 (geongangeul wihan undong, exercise for health).

Meaning-wise -기 위해서 is the same purpose as -(으)려고, only a register up: it is the choice for essays, notices, and formal speech, where -(으)려고 sounds conversational.

Step 2 - -도록 = purpose across subjects, negative purpose, and extent

-도록 attaches straight to the stem - a verb, or an adjective that can name a resulting state - with no (으), no allomorph - and does three jobs that -(으)러/-(으)려고 cannot:

• Cross-subject purpose (“so that X happens”). -(으)려고 demands one and the same subject; -도록 does not. 학생들이 이해하도록 천천히 설명해요. (haksaengdeuri ihaehadorok cheoncheonhi seolmyeonghaeyo) - I explain slowly so that the students understand. (I explain; they understand.) An adjective stem works the same way when the goal is a state: 방이 따뜻하도록 보일러를 켰어요. (bangi ttatteutadorok boilleoreul kyeosseoyo) - I turned the heating on so the room would be warm.
• Negative purpose (“so as not to X”). Build it with -지 않도록: 늦지 않도록 (neutji antorok, so as not to be late), 아이가 다치지 않도록 (aiga dachiji antorok, so the child doesn’t get hurt). This is where -도록 shines - it is smoother than -(으)려고’s -지 않으려고.
• Extent / limit (“to the point that”). Here -도록 is not purpose at all but a degree: 밤새도록 (bamsaedorok, all night long), 목이 아프도록 (mogi apeudorok, until one’s throat hurts), 죽도록 (jukdorok, to death / like crazy).

Finally, -도록 하다 is a soft directive - see to it that you…: 내일까지 끝내도록 하세요. (naeilkkaji kkeunnaedorok haseyo) - Please make sure to finish it by tomorrow. In formal commitments it appears as -도록 하겠습니다: 제가 준비하도록 하겠습니다. (jega junbihadorok hagetseumnida) - I’ll see to it that it’s prepared. This directive -도록 is a close cousin of the causative -게 하다 (lesson 56); -게 하다 makes someone do it, -도록 하다 sees to it that it gets done.

Step 3 - -(으)려면 = “if you intend to X, then Y”

-(으)려면 is literally -(으)려고 + 하면 squeezed together (if one intends to…). It sets up a goal and then states what it takes to reach it, so the main clause is almost always advice or a requirement - a -(으)세요 command or a -아/어야 해요 obligation:

Verb stem + -(으)려면 + advice / requirement -> 서울에 가려면 이 버스를 타세요. (seoure garyeomyeon i beoseureul taseyo) - To get to Seoul, take this bus.

Unlike -기 위해서 and -도록, this one does take the (으) allomorph: vowel stem -> -려면 (가다 -> 가려면), 받침 -> -으려면 (먹다 -> 먹으려면), and a ㄹ-stem keeps its ㄹ with the bare -려면 (살다 -> 살려면, sallyeomyeon, never *살으려면).

Forms & patterns

How each form attaches to the stem:

Choosing a purpose form - register, subject, and main-clause mood:

Examples

Common mistakes

• 학생들이 이해하려고 천천히 설명해요. (Haksaengdeuri ihaeharyeogo cheoncheonhi seolmyeonghaeyo.) -> 학생들이 이해하도록 천천히 설명해요. (Haksaengdeuri ihaehadorok cheoncheonhi seolmyeonghaeyo.) - -(으)려고 needs ONE subject (the explainer both intends and acts). When the purpose is about a different subject (the students understanding), use -도록.
• 합격 위해서 공부해요. (Hapgyeok wihaeseo gongbuhaeyo.) -> 합격하기 위해서 공부해요. (Hapgyeokhagi wihaeseo gongbuhaeyo.) - A verb must be nominalized with -기 before 위해서. Only a plain noun goes straight to 을/를 위해서 (합격을 위해서).
• 건강을 위해서 운동이에요. (Geongangeul wihaeseo undongieyo.) -> 건강을 위한 운동이에요. (Geongangeul wihan undongieyo.) - When “for X” modifies the following noun, 위해서 becomes the adnominal 위한. 위해(서) can only lead into a verb or clause.
• 먹려면 일찍 오세요. (Meokryeomyeon iljjik oseyo.) -> 먹으려면 일찍 오세요. (Meogeuryeomyeon iljjik oseyo.) - After a 받침, -(으)려면 inserts 으: 먹다 -> 먹으려면, not a bare *먹려면.
• 살으려면 돈이 필요해요. (Sareuryeomyeon doni piryohaeyo.) -> 살려면 돈이 필요해요. (Sallyeomyeon doni piryohaeyo.) - A ㄹ-stem keeps its ㄹ and takes the bare -려면; it never inserts 으. 살다 -> 살려면, 만들다 -> 만들려면.

Tips

• The register ladder for purpose. Same in order to, rising formality: -(으)러 (spoken, trips only) -> -(으)려고 (everyday) -> -기 위해서 (formal, essays and notices). Pick the rung that matches the situation.
• -도록 is the versatile one. It alone crosses subjects (학생들이 이해하도록) and does negative purpose cleanly (늦지 않도록, 다치지 않도록). Reach for it whenever the goal is someone else doing/not doing something.
• -도록 can stop being purpose. With 밤새-, 죽-, 목이 아프- it means to the point of: 밤새도록 (all night), 죽도록 (like crazy). If “in order to” doesn’t fit the English, you are in this extent sense.
• -(으)려면 = 려고 + 하면. Read it as “if you’re going to X, then Y,” and expect the main clause to be advice - -(으)세요 or -아/어야 해요. It answers “what does it take?”