-잖아요 Grammar in Korean: Meaning and How to Use It

What you'll learn

• Attach -잖아요 to any verb, adjective or noun and say the result with the correct tense sounds.
• Explain why -잖아요 is not a negative ending, even though it comes from -지 않아요.
• Choose between -잖아요 (the listener knows) and -거든요 (the listener does not know).
• Recognise the attention marker 있잖아요 and use it to start a topic.
• Fix the four most common learner mistakes with -잖아요.

Before you start: you should know how to find a verb stem (see verb stem), the past tense marker -았/었- and the polite 요 style. Audio plays only when you press a button.

What Does -잖아요 Grammar Mean?

-잖아요 grammar means "you know" or "as you know": the speaker presents information as something the listener already knows. The speaker is not teaching anything new. Instead the speaker brings a shared fact back into the conversation, usually to explain a reason or to correct a forgetful listener.

Here are two first examples. In the first, the speaker reminds a friend of a message. In the second, the speaker reminds a friend that a restaurant is good.

• 어제 말했잖아요. (eoje malhaetjanayo.) [어제 말핻짜나요] = "I told you yesterday, you know."
• 이 식당은 맛있잖아요. (i sikdangeun masitjanayo.) [이 식땅은 마딛짜나요] = "This restaurant is tasty, you know."

In 말했잖아요, 말했 is the past stem of 말하다 (to say, to tell), and 잖아요 is the ending. The speaker expects the listener to say "oh, right". The pattern can sound friendly when the tone is soft, and it can sound impatient when the tone is sharp, because it hints that the listener should have remembered. Next comes the rule that builds the pattern, and where the ending comes from.

How Do You Form -잖아요?

-잖아요 is formed by dropping 다 from the dictionary form and adding -잖아요 to the stem. Nothing else changes. The ending is a contraction of -지 않아요: 지 + 않 shrinks to 잖. In that older form the speaker asks a rhetorical question, "Isn't it so?" The contraction keeps only the reminding force, so 가잖아요 does not mean "does not go". It means "you know I go" or "you know it goes".

The table shows one rule on six forms. The next three parts look at the groups of stems.

Stems Ending in a Vowel

A vowel stem takes -잖아요 directly. 가다 becomes 가잖아요, 오다 becomes 오잖아요, and 유명하다 becomes 유명하잖아요. The ㅈ sound stays plain, and 잖 is spoken [자나], because the ㄶ is only a spelling: the ㅎ is silent and the ㄴ moves forward to the next syllable.

• 밖에 비가 오잖아요. (bakke biga ojanayo.) [바께 비가 오자나요] = "It's raining outside, you know."
• 그 사람은 유명하잖아요. (geu sarameun yumyeonghajanayo.) [그 사라믄 유명하자나요] = "That person is famous, you know."

Vowel stems are the simplest case. A stem with a final consonant looks the same on the page, but it sounds different.

Stems Ending in a Consonant

A consonant stem also takes -잖아요 directly, and the spelling stays whole. The sound follows the standard pronunciation rules (표준 발음법) of the 국립국어원 (National Institute of Korean Language). The ㅈ of 잖 is spoken tense after a final ㄱ, ㄷ or ㅂ, and ㅎ plus ㅈ makes [ㅊ].

Full sentences show the effect:

• 책이 너무 어렵잖아요. (chaegi neomu eoryeopjanayo.) [채기 너무 어렵짜나요] = "The book is too difficult, you know."
• 이 가방 좋잖아요. (i gabang jochanayo.) [이 가방 조차나요] = "This bag is good, you know."
• 우리 어제 만났잖아요. (uri eoje mannatjanayo.) [우리 어제 만낟짜나요] = "We met yesterday, remember?"

Write the plain spelling and say the tense sound. Irregular stems and nouns need a short note, because learners expect trouble with them.

Irregular Stems and Nouns

Irregular stems stay whole before -잖아요, because the ending starts with a consonant. Unlike the endings -네요 and -는군요, the ending does not begin with ㄴ, so ㄹ-stems do not lose their ㄹ.

• ㄹ-stems: 알다 stays 알잖아요 [알자나요], 살다 stays 살잖아요, 멀다 stays 멀잖아요, and 만들다 stays 만들잖아요. The ㄹ drops only before ㄴ, ㅂ and ㅅ.
• ㅂ-irregular: 춥다 stays 춥잖아요 [춥짜나요]. The ㅂ turns into 우 only before a vowel.
• ㄷ-irregular: 듣다 stays 듣잖아요 [듣짜나요].
• 르 and ㅡ stems: 모르다 stays 모르잖아요, and 바쁘다 stays 바쁘잖아요.
• Nouns: 이다 gives (이)잖아요. After a consonant you say 이잖아요: 학생이잖아요. After a vowel, 이 is often dropped: 의사잖아요. Time words work the same way: 오늘은 일요일이잖아요 [오느른 이료이리자나요] means "Today is Sunday, you know."

With the formation clear, one full sentence can be built step by step.

Worked Example: Building a Sentence with -잖아요

-잖아요 grammar turns a plain reason into a reminder. Follow the steps with the sentence "I'm tired today, so I can't go" to explain to a friend who already knows how busy you were.

1. Start with the plain reason. 너무 피곤해요. (neomu pigonhaeyo.) = "I'm very tired." The predicate is 피곤해요.
2. Find the dictionary form. 피곤해요 comes from 피곤하다 (to be tired). The stem is 피곤하.
3. Add -잖아요 to the stem. 피곤하 + 잖아요 = 피곤하잖아요.
4. Put the result first. Korean speakers often state the result and then add the reminder: 오늘은 못 가요.
5. Rebuild the sentence. 오늘은 못 가요. 너무 피곤하잖아요. (oneureun mot gayo. neomu pigonhajanayo.) [오느른 몯 까요. 너무 피곤하자나요] = "I can't go today. I'm so tired, you know."

You will know it worked when the reason ends in 잖아요 and the listener could say "yes, I know". The most common slip at this step is using the pattern when the listener does not know the reason; the mistakes section returns to that. A reminder can appear in more than one tense, and each form has limits.

Which Tenses and Sentence Types Work with -잖아요?

-잖아요 works in the present and the past, in statements, and with the honorific -시-. It does not work in commands or suggestions. The tense marker goes between the stem and the ending.

The negative row is worth noticing. To say "you know he doesn't come", you put 안 before the verb: 안 오잖아요. The ending itself never carries a negative meaning. A statement with -잖아요 usually ends with a falling tone. A rising tone is possible too, and it asks for agreement ("Right?").

• 사장님이 곧 오시잖아요. (sajangnimi got osijanayo.) [사장니미 곧 오시자나요] = "The president is coming soon, you know."

Commands and suggestions never take -잖아요. These limits make the closest neighbour, -거든요, the most useful comparison.

How Is -잖아요 Different from -거든요 and -지요?

-잖아요 treats the information as shared with the listener, while -거든요 gives information the listener does not have. The contrast is about who knows the fact. A third neighbour, -지요/-죠, asks for agreement without any hint of impatience.

Here is one situation with each ending. A colleague asks why you cannot join the team dinner. 일이 있거든요 ("I have work, you see") gives a reason that the colleague did not know. If the colleague asked the same question a second time after you had already explained, 일이 있다고 했잖아요 ("I said I have work, remember") would remind them. If you are checking whether the colleague agrees that the dinner is tomorrow, 내일이죠? ("It's tomorrow, right?") asks for agreement. The full lessons are -거든요 and -지요/-죠, and the side-by-side pages are -잖아요 vs -거든요 and -지요 vs -잖아요. These contrasts lead to the smaller variations of the pattern.

Variations and Edge Cases of -잖아요

-잖아요 has four common variations: a shared reason, an attention marker, a casual form and a reproachful tone. Each one is short, and each appears in real conversation.

• Shared reason. The reason comes after the result: 오늘은 못 가요. 너무 피곤하잖아요. The listener knows the reason and does not need to be told.
• Attention marker. 있잖아요 at the start of a sentence means "you know what?" or "listen": 있잖아요, 제가 할 말이 있어요 ("You know, I have something to say"). Here 있잖아요 is spoken [읻짜나요], and it asks for the listener's attention before the topic.
• Casual 잖아. Drop the 요 with friends: 어제 말했잖아. The meaning is the same.
• Reproachful tone. A sharp tone makes -잖아요 sound like a complaint: 제가 어제 말했잖아요! The same words in a soft voice are a friendly reminder.

Another common sentence links a shared fact with a conclusion: 오늘은 일요일이잖아요. 회사에 안 가요 ("It's Sunday, you know. I'm not going to the office"). The shared fact (Sunday) explains the result.

This lesson covers the present, past and honorific forms used in daily conversation, not the full range of Korean pragmatic endings. Endings such as -(으)ㄴ/는데요 ("but ...") and -거든요 ("you see") belong to their own lessons. The mistakes below show where the boundary with other patterns causes real errors.

What Mistakes Do Learners Make with -잖아요?

Learners most often get the knowledge status, the meaning or the politeness wrong. Four mistakes appear again and again.

1. Using it for new information. Learners often assume that -잖아요 is a softener for any explanation. Actually it says the listener knows. 저는 일이 있잖아요 sounds as if the listener should know about your work. For new background use 일이 있거든요.
2. Reading it as a negative. The ending comes from -지 않아요, so learners translate 가잖아요 as "does not go". The correct reading is "you know I go". For "does not go" say 안 가요 or 가지 않아요.
3. Using it to correct an older person. The reminder suggests that the listener forgot. 사장님, 어제 말씀드렸잖아요 can sound rude. Many speakers use -지요 or a longer, softer sentence instead.
4. Spelling it by sound. The pronunciation [자나요] tempts learners to write 자나요 or 잔아요. The correct spelling is 잖아요, with the ㄶ final on 잖.

A quick check for any -잖아요 sentence: Does the listener already know this? Is my tone friendly? Is the person someone I can remind? If the answers are yes, the sentence is sound.

The practice set below tests these points directly.

Practice and Answers

Try the four items before you read the answer key. Cover the answers with your hand.

1. Choose the ending. A friend asks why you are not eating the cake, though you told them you are on a diet yesterday. Reply: 어제 ___. (말했잖아요 / 말했거든요)
2. Fix the error. A learner tells a friend 책이 어려워잖아요 about a hard book. Correct the stem.
3. Translate. "It's raining now, you know." Use 비(가) 오다 and -잖아요.
4. Write your own. Write one sentence that gives a shared reason, using -잖아요. Then change it to the casual form.

Answer key

1. 말했잖아요. The friend should already know, so the reminder fits.
2. 책이 어렵잖아요. The ending attaches to the bare stem 어렵, so 어려워잖아요 is wrong. It is pronounced [어렵짜나요].
3. 지금 비 오잖아요. (jigeum bi ojanayo.) [지금 비 오자나요] = "It's raining now, you know."
4. Answers vary. Check that the stem is bare and that the casual form drops 요. An example: 오늘은 월요일이잖아요 becomes 오늘은 월요일이잖아 ("It's Monday, you know").

If you can complete items 1 to 3 without the key, you can use the pattern in conversation. The lesson now hands off to related patterns.

What Should You Learn Next after -잖아요 Grammar?

After -잖아요 grammar, learn the ending for new reasons, then the ending for agreement. This lesson teaches the reminder and does not cover background endings, softened statements or retrospective endings in depth. Those live on their own pages.

1. Start with -거든요, which gives a reason the listener does not know.
2. Continue with -지요/-죠, which asks for agreement or states a fact softly.
3. Compare the first pair side by side in -잖아요 vs -거든요, and the second in -지요 vs -잖아요.
4. Return to Exclamations and Realization to see every lesson in this set, or to the Intermediate Grammar list for other B1 patterns.

With these steps, -잖아요 becomes automatic: take the bare stem, add 잖아요, and keep it for facts that the listener already shares.

Frequently Asked Questions

What does -잖아요 mean in one sentence?

-잖아요 means "you know" or "as you know". The speaker reminds the listener of something they both know or should remember. 어제 말했잖아요 means "I told you yesterday, you know." It can give a reason, and with a sharp tone it can sound a little impatient.

How do I attach -잖아요 to a verb or adjective?

Drop 다 and add -잖아요 with no linking vowel: 가다 becomes 가잖아요, 어렵다 becomes 어렵잖아요, and 이다 becomes (이)잖아요. A stem that ends in ㄹ keeps it, so 알다 becomes 알잖아요. The same rule works for verbs, adjectives and nouns.

Can -잖아요 be used in the past tense?

Yes. Put -았/었- before it: 말했잖아요 means "I told you," and 만났잖아요 means "we met." The past form reminds the listener of an event they should remember. It is one of the most common uses, as in 어제 말했잖아요 ("I told you yesterday"), and the speaker usually expects a nod.

Is -잖아요 polite or casual?

-잖아요 is polite grammar, the 요 form of the casual -잖아, but the meaning can feel pushy. A friendly tone sounds natural; a sharp tone sounds like a scolding. With a boss or a teacher, many speakers choose -지요 or a plain explanation instead, because the reminder suggests that the listener forgot.

What is the most common mistake with -잖아요?

The most common mistake is using it for new information. The listener does not know your reason, so 일이 있잖아요 sounds as if they should know about your work. Use -거든요 for background that is new to the listener. A second mistake is reading -잖아요 as a negative "does not".

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