Past Tense -았/었 in Korean

In Brief

Korean marks the past by adding -았/었- to a verb stem: use -았- after ㅏ or ㅗ, and -었- after other vowels. With the everyday polite ending, this gives forms such as 갔어요 “went,” 먹었어요 “ate,” and 했어요 “did.” Many forms contract, but the underlying rule remains the same.

Overview

The Korean past tense lets you describe completed actions and earlier states: where someone went, what you ate, how the weather was, or whether a film was interesting. It is a core A1 pattern and builds directly on the everyday polite -아/어요 style.

The central piece is -았/었-, a tense marker (a form that locates an event in time). It follows the stem—the part obtained by removing -다 from a dictionary form—and comes before the final speech-level ending. Thus 먹다 has the stem 먹-, and 먹- + -었- + -어요 becomes 먹었어요.

Unlike English verbs, Korean verbs do not change according to the subject. 먹었어요 can mean “I ate,” “she ate,” “we ate,” or “they ate.” Korean also often omits a subject that listeners can recover from context. Time expressions such as 어제 “yesterday” help, but a past ending can stand on its own.

How It Works

1. Find the stem

Remove the dictionary ending -다.

Dictionary form	Meaning	Stem
가다	to go	가-
먹다	to eat	먹-
배우다	to learn	배우-
재미있다	to be fun/interesting	재미있-
하다	to do	하-

Korean “descriptive verbs,” such as 춥다 “to be cold” and 좋다 “to be good,” express qualities that English usually expresses with “be + adjective.” They take the past marker just as action verbs do.

2. Choose -았- or -었-

Look at the final vowel of the stem. This is the same vowel choice used for -아/어요.

Stem’s final vowel	Marker	Example
ㅏ or ㅗ	-았-	살다 → 살았어요 “lived”
Any other vowel	-었-	먹다 → 먹었어요 “ate”
하다 and compounds in 하다	traditionally -였-, contracted to 했-	공부하다 → 공부했어요 “studied”

The beginner formula is:

stem + -았/었- + final ending

For everyday polite conversation, the final ending is -어요, so you will most often learn the combined form -았/었어요.

3. Apply normal vowel contractions

When a vowel-final stem meets -았/었어요, the vowels usually merge. Do not pronounce an extra syllable that is absent from the standard spelling.

Combination	Result	Formation
ㅏ + 았어요	ㅏ + ㅆ어요	가다 → 갔어요
ㅗ + 았어요	ㅘ + ㅆ어요	오다 → 왔어요
ㅓ + 었어요	ㅓ + ㅆ어요	서다 → 섰어요
ㅜ + 었어요	ㅝ + ㅆ어요	배우다 → 배웠어요
ㅣ + 었어요	ㅕ + ㅆ어요	마시다 → 마셨어요
ㅚ + 었어요	ㅙ + ㅆ어요	되다 → 됐어요
하 + 였어요	했어요	하다 → 했어요

With stems already ending in ㅐ or ㅔ, the written vowel normally remains: 보내다 → 보냈어요 “sent,” 세다 → 셌어요 “was strong/counting: counted,” depending on the verb.

The consonant ㅆ is a useful visual clue. It closes the contracted syllable in 갔-, 왔-, and 했-, after which the ending -어요 follows.

4. Watch common stem changes

The past tense does not create a separate collection of irregular verbs. Rather, the same stem changes seen before -아/어요 also appear before -았/었어요.

Pattern	Dictionary form	Polite past	Meaning
ㅂ change	춥다	추웠어요	was cold
ㄷ change	듣다	들었어요	listened/heard
르 change	모르다	몰랐어요	did not know
ㅡ loss	쓰다	썼어요	wrote/used
ㅅ loss	짓다	지었어요	built
regular-looking ㄹ stem	만들다	만들었어요	made

Not every verb containing these consonants changes. For example, 받다 → 받았어요 “received” and 입다 → 입었어요 “wore” are regular. Learn the dictionary form together with its familiar polite form.

5. Add the appropriate speech-level ending

The past marker itself stays recognizable while the final ending changes to fit the social setting.

Style	가다 “to go”	먹다 “to eat”	Typical use
Everyday polite	갔어요	먹었어요	Most ordinary polite conversation
Formal polite	갔습니다	먹었습니다	Presentations, announcements, formal service contexts
Intimate/casual	갔어	먹었어	Close friends, family, or speech to younger people
Plain written	갔다	먹었다	Narration, diaries, reports, dictionary-style statements

For a beginner, -았/었어요 is the safest productive form. A bare form such as 갔어 is not merely a shortened polite form: it signals a different relationship with the listener.

Questions and negatives

In everyday polite speech, a statement becomes a question mainly through intonation and punctuation:

• 먹었어요. — “I/you ate.”
• 먹었어요? — “Did you eat?”

There is no separate equivalent of English “did.” Negation follows the normal Korean negative patterns:

• 안 갔어요. — “I didn’t go.”
• 가지 않았어요. — “I did not go.”
• 못 먹었어요. — “I couldn’t eat / failed to eat.”

With short 안 and 못 negatives, the negative word comes before the verb or before the 하다 part of many compounds: 공부 안 했어요 “I didn’t study.” The longer -지 않다 construction carries the past on 않다: 공부하지 않았어요.

Examples in Context

Korean	English	Note
어제 학교에 갔어요.	I went to school yesterday.	가다 → 갔어요
아침에 빵을 먹었어요.	I ate bread in the morning.	Regular consonant-final stem
주말에 뭐 했어요?	What did you do over the weekend?	Natural polite question
친구를 만났어요.	I met a friend.	만나다 → 만났어요
한국어를 배웠어요.	I learned Korean.	ㅜ + 었어요 → 웠어요
커피를 마셨어요.	I drank coffee.	ㅣ + 었어요 → 셨어요
영화가 재미있었어요.	The film was interesting.	Past state with a descriptive verb
어제는 정말 추웠어요.	It was really cold yesterday.	ㅂ-changing 춥다
음악을 들었어요.	I listened to music.	ㄷ-changing 듣다
그 사실을 몰랐어요.	I didn’t know that fact.	Lexically negative 모르다
숙제를 안 했어요.	I didn’t do the homework.	Short negation
너무 바빠서 점심을 못 먹었어요.	I was so busy that I couldn’t eat lunch.	못 expresses inability or failure
벌써 끝났어요?	Has it finished already?	Past form can translate as English present perfect
민수 씨는 집에 왔습니다.	Minsu came home.	Formal polite style

English translations often require a stated subject, but the Korean examples frequently do not. Context tells you whether 갔어요 means “I went,” “she went,” or “they went.”

Common Mistakes

Adding 었어요 without contracting

• Wrong: 가었어요
• Right: 갔어요
• Why: The stem vowel ㅏ calls for -았-, and 가 + 았어요 contracts to 갔어요.

Choosing by the final letter rather than the final vowel

• Wrong: 먹았어요
• Right: 먹었어요
• Why: The stem 먹- ends in a consonant, but its final vowel is ㅓ, so it takes -었-. Look inside the final syllable for the vowel.

Treating 하다 as a regular visible combination

• Wrong: 공부하었어요
• Right: 공부했어요
• Why: 하다 forms the contracted past 했어요. This applies to compounds such as 일하다 → 일했어요 and 운동하다 → 운동했어요.

Using an English-style auxiliary

• Wrong: 했어요 갔어요 for “did go”
• Right: 갔어요
• Why: Korean places past time directly on the main verb. 하다 is not inserted as an auxiliary corresponding to English “did.”

Putting past marking on the lexical verb in -지 않다

• Wrong: 가지었어요 않아요
• Right: 가지 않았어요
• Why: In this negative construction, 않다 is the final verb and receives the past marker.

Assuming every past event needs 어제

• Unnatural as a rule: adding 어제 to every past sentence
• Natural: 점심 먹었어요? “Did you eat lunch?”
• Why: -았/었- already marks the past. Add a time word only when the time matters or is not clear.

Usage Notes

One Korean form, several possible English tenses

Korean -았/었- marks an event or state as prior to the current reference point, but it does not map perfectly onto one English tense. Depending on context, 먹었어요 may be “I ate,” “I have eaten,” or even the natural reply “Yes, I have.” Do not force a word-for-word distinction between the English simple past and present perfect into the Korean form.

Some completed changes are expressed with a Korean past form even when English prefers a present result:

• 문이 열렸어요. — “The door has opened” or “The door is open now.”
• 준비됐어요. — “It’s ready.”
• 알겠어요. — “I understand / Got it.”

The exact interpretation comes from the verb and the situation, not from the ending alone.

Past states are formed directly

English adds “was” before an adjective, but Korean descriptive verbs carry tense themselves: 비싸다 → 비쌌어요 “was expensive,” 좋다 → 좋았어요 “was good.” Do not add a separate word meaning “was.”

The copula 이다 (“to be” after a noun) has its own common past forms: 학생이었어요 “was a student” and, commonly after a vowel, 의사였어요 “was a doctor.” The negative copula is 아니었어요 “was not.”

Politeness and tense are separate choices

갔어요, 갔습니다, and 갔어 all refer to the past. What changes is the speech level—the way the ending presents the relationship between speaker and listener. Use -았/었어요 when you need normal everyday politeness, not because the past tense itself is inherently polite.

Beyond the Basics / Advanced Use

You do not need to master the following points at A1, but they explain forms you will meet later.

Past tense can combine with other endings

Because -았/었- sits before the final ending, it appears in many larger patterns:

Form	Example	Meaning
-았/었지만	갔지만	went, but…
-았/었는데	먹었는데	ate, and/but/as background…
-았/었으면	알았으면	if (someone) had known / if only…
-았/었던	살았던 집	the house where someone once lived

These forms add contrast, background, conditions, or noun modification. Their full meaning cannot always be predicted by translating the past marker alone.

-았었- can emphasize a more remote or discontinued past

Korean sometimes uses a doubled-looking form, -았/었었-, as in 살았었어요. It may emphasize that a situation existed in the past but no longer does, or place it as a past-before-past event. Ordinary past narration usually needs only 살았어요. Overusing -았었어요 because English has “had lived” will sound forced; context often makes the sequence clear without it.

Completed past versus remembered experience

The basic past -았/었- reports an earlier event or state. Later, you will encounter -더-, which presents something as recalled from the speaker’s past observation or experience. Compare the neutral 맛있었어요 “It was delicious” with 맛있더라고요, roughly “I found/remembered that it was delicious.” The second form adds the speaker’s retrospective viewpoint, not just past time.

Past-time noun modifiers use a different system

Before a noun, Korean does not simply attach -았/었어요. Completed actions commonly use -(으)ㄴ: 어제 본 영화 “the film I saw yesterday.” Forms such as 봤던 영화 add nuances of recollection or previous experience. Treat noun-modifying forms as a related system rather than cutting -어요 off a sentence form.

Practice Tips

1. Build three-form sets. Take five common verbs and write the dictionary form, present polite form, and past polite form: 가다 → 가요 → 갔어요. This makes the shared vowel and contraction patterns visible.
2. Sort by sound pattern. Practise small groups such as 오다 → 왔어요, 배우다 → 배웠어요, and 마시다 → 마셨어요. Say the contracted result aloud rather than spelling out the hidden pieces.
3. Keep a two-minute yesterday log. Write three sentences beginning with useful time phrases such as 어제, 아침에, and 주말에. Include one action, one negative, and one past state—for example, what you did, what you did not do, and how the day was.

Related Concepts

• Prerequisite: Polite Ending -아/어요 — supplies the everyday polite ending and the same vowel-harmony and contraction patterns.
• Next step: Retrospective -더- — adds the nuance of recalling something personally observed or experienced in the past.