-을 때: When — the Moment / Situation

When — builds a time/situation phrase with the future/plain modifier + 때.

Before this, make sure you know: -아요 / -어요 , -으면 , -고 있다

How to form it

When	Form	Example
Stem ends in a consonant (not ㄹ)	-을 때	먹다 → 먹을 때 / 있다 → 있을 때
Stem ends in a vowel or ㄹ	-ㄹ 때	가다 → 갈 때 / 살다 → 살 때
Past situation (common twin)	-은/ㄴ 때	갔을 때 / 학생일 때

-을 때 builds a when… phrase.

저는 시간이 있을 때 요리해요 — when I have time, I cook.

Forms

Stem	Form
Consonant (not ㄹ)	-을 때
Vowel or ㄹ	-ㄹ 때

바쁠 때 커피를 마셔요.     When I’m busy, I drink coffee.
한국에 갈 때 연락해요.     Contact me when you go to Korea.
혼자 있을 때 음악을 들어요. When I’m alone, I listen to music.

Not -(으)면

Form	Job
-으면 -(으)면	if / when as a condition
-을 때	when as a time/situation phrase

Overlap in English when is huge. Korean still chooses: condition → -(으)면; “at the time when…” → -을 때.

Past twin

You will also meet -았을 때 / -은 때 for finished situations (한국에 살았을 때…). -았-/-었- lives in that past marking — do not also force -었- onto the final verb without a reason.

Hobby talk

This unit’s theme is hobbies: 주말에 시간이 있을 때… is the natural frame for what you do in free time.

Do not confuse it with

-으면

if, when — the all-purpose conditional

-고 있다

be doing — the progressive

-았-/-었-

past tense — built on the same stem rule as 해요체

Taught alongside this

In the Sejong course this appears in 저는 시간이 있을 때 요리해요 — Sejong Korean 2, Unit 17, on the theme of 취미. These come with it:

-게 되다 ending up that way — a change you did not choose 에게로 toward a person — direction rather than destination

Words used above

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때ttaetime; moment; occasion

취미chwimihobby

요리하다yorihadato cook

시간sigantime

Quick check

No sign-up, no score saved — just see if it stuck.

1. What does -을 때 mark?

2. -을 때 vs -(으)면?

3. 시간이 있을 때 요리해요 — correct reading?

Common questions

Is -을 때 always future?

The -을/ㄹ modifier here often just links to 때 without a strong future claim. Past scenes commonly use -았을 때 / -은 때 as well — learn -을 때 from this unit first.

있을 때 vs 있고 있을 때?

있을 때 is enough for 'when I have…'. [[g:go-itda]] adds progressive when you need 'while in the middle of…'.

Can I say 먹었을 때였어요 with double past everywhere?

Keep tense mostly in one place. Prefer 학생일 때 / 한국에 갔을 때 patterns rather than stacking every clause with -었-.

Noun + 때?

Yes: 방학 때, 어릴 때 (lexical). From verbs, use the modifier + 때.