Verbs · ㄹ stem

줄다 conjugation

to decrease; to shrink · julda · sounds like [줄다]

Short answer: “To decrease” in Korean is 줄다 (julda), which also means to shrink. Polite present: 줄어요 (jureoyo); past: 줄었어요 (jureosseoyo); future: 줄 거예요. It is regular, but its ㄹ drops before ㄴ, ㅂ and ㅅ.

Present줄어요[주러요] · jureoyo
Past줄었어요[주러써요] · jureosseoyo
Future줄 거예요[줄 꺼예요] · jul geoyeyo
Negative안 줄어요[안 주러요] · an jureoyo

Opposite: 늘다 — to increase

줄다 in sentences

몸무게가 줄었어요.I’ve lost weight.
바지가 빨래 후에 줄었어요.The trousers shrank in the wash.

All forms of 줄다

Present
Polite (해요) is the everyday safe choice; formal (합니다) is for news, announcements and work; casual (반말) is for close friends and younger people.
Form	Korean	Sounds like	Romanized
polite-아/어요	줄어요	[주러요]	jureoyo
formal-(스)ㅂ니다	줍니다	[줌니다]	jumnida
casual-아/어	줄어	[주러]	jureo
plain (written)-(느)ㄴ다	준다	[준다]	junda
formal question-(스)ㅂ니까?	줍니까?	[줌니까]	jumnikka?
is …ing (polite)-고 있어요	줄고 있어요	[줄고 이써요]	julgo isseoyo

Past
Form	Korean	Sounds like	Romanized
polite-았/었어요	줄었어요	[주러써요]	jureosseoyo
formal-았/었습니다	줄었습니다	[주럳씀니다]	jureotseumnida
casual-았/었어	줄었어	[주러써]	jureosseo
plain (written)-았/었다	줄었다	[주럳따]	jureotda

Future
Form	Korean	Sounds like	Romanized
polite — will-(으)ㄹ 거예요	줄 거예요	[줄 꺼예요]	jul geoyeyo
formal-(으)ㄹ 겁니다	줄 겁니다	[줄 껌니다]	jul geomnida
casual-(으)ㄹ 거야	줄 거야	[줄 꺼야]	jul geoya
formal — I will (intention)-겠습니다	줄겠습니다	[줄겓씀니다]	julgetseumnida

Negative
Form	Korean	Sounds like	Romanized
not (short)안 …	안 줄어요	[안 주러요]	an jureoyo
did not안 …았/었어요	안 줄었어요	[안 주러써요]	an jureosseoyo
not (long)-지 않아요	줄지 않아요	[줄지 아나요]	julji anayo
cannot못 …	못 줄어요	[몯 쭈러요]	mot jureoyo

Honorific
Add -(으)시- when the subject is someone you respect (a teacher, a customer, an older person) — not yourself.
Form	Korean	Sounds like	Romanized
honorific — present-(으)세요	주세요	[주세요]	juseyo
honorific — past-(으)셨어요	주셨어요	[주셔써요]	jusyeosseoyo
honorific — formal-(으)십니다	주십니다	[주심니다]	jusimnida

Connecting
Form	Korean	Sounds like	Romanized
… and-고	줄고	[줄고]	julgo
… so / and then-아/어서	줄어서	[주러서]	jureoseo
if …-(으)면	줄면	[줄면]	julmyeon
… but-지만	줄지만	[줄지만]	juljiman
because …-(으)니까	주니까	[주니까]	junikka
… and / but (background)-는데	주는데	[주는데]	juneunde
even if …-아/어도	줄어도	[주러도]	jureodo
while …-(으)면서	줄면서	[줄면서]	julmyeonseo
before …-기 전에	줄기 전에	[줄기 저네]	julgi jeone
after …-(으)ㄴ 후에	준 후에	[준 후에]	jun hue

Describing a noun
These go before a noun: “the food (that) I ate”, “a cold day”.
Form	Korean	Sounds like	Romanized
(that) … now-는	주는	[주는]	juneun
(that) …ed-(으)ㄴ	준	[준]	jun
(that) will …-(으)ㄹ	줄	[줄]	jul

Useful patterns
Form	Korean	Sounds like	Romanized
I want to …-고 싶어요	줄고 싶어요	[줄고 시퍼요]	julgo sipeoyo
can …-(으)ㄹ 수 있어요	줄 수 있어요	[줄 쑤 이써요]	jul su isseoyo
cannot …-(으)ㄹ 수 없어요	줄 수 없어요	[줄 쑤 업써요]	jul su eopseoyo
have to …-아/어야 해요	줄어야 해요	[주러야 해요]	jureoya haeyo
may … / it’s OK to …-아/어도 돼요	줄어도 돼요	[주러도 돼요]	jureodo dwaeyo
must not …-(으)면 안 돼요	줄면 안 돼요	[줄면 안 돼요]	julmyeon an dwaeyo
…ing (noun)-기	줄기	[줄기]	julgi

How 줄다 changes

줄다 ends in ㄹ. The ㄹ drops before ㄴ, ㅂ and ㅅ — 주는, 줍니다, 주세요 — and endings written -(으) never add 으: 줄면, 줄. Everything else is regular: 줄어요. (Grammar books count this as regular, but it trips up learners.)

How every verb type works → · Why it sounds like that →

Questions

How do you say “decrease” in Korean?

“To decrease” is 줄다 (julda), pronounced [줄다]. In a sentence: 몸무게가 줄었어요. — I’ve lost weight.

What is the past tense of 줄다?

줄었어요 (jureosseoyo) is the polite past tense of 줄다 (“to decrease”). Formal: 줄었습니다; casual: 줄었어.

How do you say 줄다 politely?

Everyday polite: 줄어요 (jureoyo). Formal: 줍니다. Casual, with close friends: 줄어.

Is 줄다 irregular?

No. 줄다 ends in ㄹ. The ㄹ drops before ㄴ, ㅂ and ㅅ — 주는, 줍니다, 주세요 — and endings written -(으) never add 으: 줄면, 줄. Everything else is regular: 줄어요. (Grammar books count this as regular, but it trips up learners.)

More ㄹ-stem words like 줄다

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Forms follow 한글 맞춤법 (Korean spelling rules); pronunciation follows 표준 발음법 and romanization follows 국어의 로마자 표기법 (Revised Romanization). Last updated October 16, 2026. How we check