Korean Irregular Verbs Explained

Korean adjectives conjugate like verbs, so these rules cover them too. 춥다 is an adjective. Each of the 792 words in our Korean conjugation tables has a table that names its class, and the label links to the matching section below.

The classes at a glance

That's 603 verbs and 189 adjectives from the National Institute of Korean Language's vocabulary list for learners (한국어 학습용 어휘 목록), its 212 beginner words first, then the intermediate ones. The last six classes are the irregular ones, 82 words in all. ㄹ stems, ㅡ stems and 하다 words change their stems too, by rules of their own, and our tables label them separately. The forms are built by the standard rules, and each word's class is read from its entry in English Wiktionary.

Regular verbs and adjectives

A regular word keeps its stem in every form. Take -다 off the dictionary form and you have the stem, 먹- for 먹다. The endings go straight onto it: 먹어요, 먹습니다, 먹었어요, 먹으면, 먹는. Of our 792 words, 405 are regular.

The stem still decides which version of an ending you use. After a consonant, the formal ending is -습니다, and endings such as -(으)면 keep their 으, as in 먹으면. After a vowel, it's -ㅂ니다 and the 으 goes, so 가다 is 갑니다. The polite ending is -아요 when the stem's last vowel is ㅏ or ㅗ, and -어요 after any other vowel.

Vowel stems also merge with the ending. 가다 is 가요 and 갔어요, 보다 becomes 봐요, 주다 줘요, 마시다 마셔요 and 되다 돼요. The long spellings 보아요, 마시어요 and 되어요 are correct too, and our quiz takes them.

하다 words

하다 (to do) has forms of its own. Its polite present is 해요 and its past 했어요, while 합니다 and 하세요 follow the usual rules. Every word that ends in 하다 conjugates the same way, so 공부하다 (to study) is 공부해요. That's 249 of our words, all covered once you know 하다. You'll also meet 하여요 and 하였어요, older long spellings of 해요 and 했어요, and the quiz takes them.

With a noun + 하다 verb, the negative goes inside the word. 안 and 못 sit between the noun and 하다, as in 공부 안 해요 and 공부 못 해요. That's true of 151 of our 하다 verbs. 좋아하다 isn't a noun plus 하다, so 안 stays in front: 안 좋아해요.

ㄹ stems

A stem that ends in ㄹ drops it before ㄴ, ㅂ and ㅅ. So 살다 (to live) becomes 삽니다, 사세요, 사는 and 사니까, and 산 in the past form before a noun. Before any other letter the ㄹ stays: 살아요, 살면, 살 거예요, 살고.

Watch the 으 too. Endings that add 으 after a consonant don't add it after ㄹ, so it's 살면, not 살으면. Our list has 40 ㄹ stems, among them 만들다 (to make), 알다 (to know), 길다 (to be long), 멀다 (to be far), 놀다 (to play), 팔다 (to sell) and 열다 (to open).

ㅡ stems

A stem that ends in the vowel ㅡ drops it before -아/어, and the vowel in front decides which of the two. 쓰다 and 크다 (to be big) are one syllable, so they take 어: 써요, 커요. 바쁘다 (to be busy) has ㅏ in front of the ㅡ, so it's 바빠요. 예쁘다 (to be pretty) has ㅖ, so it's 예뻐요. Before other endings the ㅡ stays.

There are 16 in our list, among them 아프다, 슬프다, 기쁘다, 끄다 and 모으다. 따르다 and 들르다 belong here too, though they end in 르: 따라요, 들러요. They're the look-alikes of the 르 irregulars below.

ㅂ irregular

Before a vowel, the ㅂ at the end of these stems turns into 우. 춥다 (to be cold) becomes 추워요, 추우면 and 추운, and 어렵다 (to be difficult) becomes 어려워요. 돕다 (to help) and 곱다 take 와 instead: 도와요, 고와요. Before a consonant the ㅂ stays.

Our list has 41 ㅂ irregular words. Of those, 37 are adjectives and only 4 are verbs: 돕다, 눕다, 굽다 and 줍다. 눕다 is to lie down, 굽다 to grill and 줍다 to pick up.

Not every ㅂ stem is irregular. Our list has 8 regular ones, 잡다, 입다, 뽑다, 좁다, 집다, 뒤집다, 씹다 and 갈아입다, and they keep their ㅂ, as in 입어요 and 입으면.

ㄷ irregular

Before a vowel, the ㄷ turns into ㄹ. 듣다 (to listen) becomes 들어요, 들으면 and 들은, but keeps its ㄷ in 듣고 and 듣습니다. Our list has 5 of them: 듣다, 묻다, 걷다, 싣다 and 알아듣다. 묻다 is to ask, 걷다 to walk, 싣다 to load, and 알아듣다 (to understand) follows 듣다.

The other ㄷ stems in our list keep the ㄷ in every form. 받다, 닫다, 얻다, 믿다, 쏟다 and 뻗다 are regular, so 받다 (to receive) is 받아요.

ㅅ irregular

Before a vowel, the ㅅ drops, and the two syllables stay apart instead of merging as they would for a vowel stem. 짓다 (to build) becomes 지어요, 지으면 and 지은, and 낫다 becomes 나아요. Before a consonant the ㅅ stays.

There are 4 in our list: 짓다, 낫다, 붓다 and 젓다. 웃다, 씻다 and 벗다 look the same but are regular: 웃어요.

ㅎ irregular

These stems drop their ㅎ before -아/어, -(으)면 and -(으)ㄴ, and before -아/어 the vowel turns into ㅐ as well. 그렇다 (to be so) becomes 그래요, 그러면 and 그런, and 빨갛다 (to be red) becomes 빨개요 and 빨간. 하얗다 (to be white) gives 하얘요. Before -습니다, -지만 and -고 the ㅎ stays: 그렇습니다, 그렇지만, 그렇고.

All 11 in our list are adjectives: the colors 빨갛다, 노랗다, 파랗다, 까맣다 and 하얗다, the words for "like this," "like that" and "how," 이렇다, 그렇다, 저렇다 and 어떻다, and 커다랗다 and 조그맣다. The other ㅎ stems in our list are regular. 좋다 (to be good), 놓다, 넣다, 낳다, 닿다 and 쌓다 keep the ㅎ, so it's 좋아요 and 좋은.

르 irregular

Before -아/어, a 르 stem drops its ㅡ and doubles the ㄹ, which gives ㄹ라 or ㄹ러. The vowel in front decides which, as it does for -아요 and -어요. 모르다 (to not know) becomes 몰라요 and 몰랐어요, and 부르다 becomes 불러요. Before other endings the stem doesn't change: 모르면, 모릅니다, 모르는.

Our list has 19, among them 다르다 (to be different), 빠르다 (to be fast), 흐르다 (to flow), 자르다 (to cut), 고르다 (to choose), 누르다 (to press), 서두르다 (to hurry) and 배부르다 (to be full). 따르다 and 들르다 also end in 르, but they're ㅡ stems, with one ㄹ: 따라요, 들러요.

러 irregular

Only 2 words in our list are 러 irregular: 이르다 (to reach) and 푸르다 (to be blue or green). They keep their 르 and add 러 where other words add 어: 이르러요, 푸르러요.

Watch 이르다. Meaning "to tell" or "to be early," it's a different word and a 르 irregular, 일러요. Our list has only the 이르다 that means "to reach."

One more type, the 우 irregular, has the verb 푸다, which becomes 퍼요. It isn't in our list.

Telling regular and irregular look-alikes apart

The dictionary form won't tell you which class a word is in. 입다 and 춥다 both end in ㅂ, 받다 and 듣다 in ㄷ, 웃다 and 짓다 in ㅅ, and 좋다 and 그렇다 in ㅎ. The polite present will, because every irregular type changes before -아요/어요.

So learn each new word with its -아요/어요 form, and the class comes with it. Two shortcuts work for our list. Only 4 verbs are ㅂ irregular, so any other verb in ㅂ, such as 입다 or 잡다, is regular, and 좁다 is the one regular ㅂ adjective. And all 11 ㅎ irregulars are adjectives, so a verb in ㅎ, such as 놓다 or 넣다, is regular.

To practice the difference, put 입다, 춥다, 받다 and 듣다 on one worksheet and tick only the present. Or tick the irregular verbs in the quiz and keep going until 추워요 comes without thinking.

Honorific verbs and words with no negative

The honorific usually adds -(으)시- to the stem, as in 하세요, and 사세요 from 살다. A few verbs use a different word instead. 먹다 has 드세요 (the quiz also takes 먹으세요), 자다 has 주무세요, 말하다 has 말씀하세요 and 죽다 has 돌아가세요. 있다 has two: 계세요 when it's about a person and 있으세요 for what someone has. 없다 has 없으세요. 계시다, 주무시다 and 드시다 are honorific already, and an honorific verb has no casual commands.

있다, 없다 and 알다 take neither negative. Their opposites are words of their own: 있다 and 없다 are a pair, and the opposite of 알다 is 모르다. 모르다 itself has no 안 form, so you won't find 안 몰라요 in our tables, but it keeps 모르지 않아요.

Frequently asked questions

Licenses and credits

The verbs and adjectives are those of the 한국어 학습용 어휘 목록 of the National Institute of Korean Language (KOGL Type 1). Each word's conjugation class and its forms were checked against English Wiktionary through kaikki.org (CC BY-SA 4.0), and the romanization is by koroman (MIT). The forms are built by the standard rules, and the English meanings are written for NexaProva.