-아/어 보니(까) Grammar in Korean: Meaning and How to Use It

What you'll learn

• Attach -아/어 보니(까) to verbs, including vowel, ㅡ, ㄹ, ㅂ and ㄷ stems.
• Write the finding clause in the right tense.
• Tell -아/어 보니(까) apart from -다 보니(까), -(으)니까 and -았/었더니.
• Use the fixed phrase 알고 보니 ("it turned out").

Prerequisites: the polite ending -아요/어요 and the pattern -다 보니(까). Time: about 15 minutes.

Key facts

• -아/어 보니(까) means "when I tried it, I found out".
• The form is the 아/어 form of the stem + 보니까, such as 먹어 보니까 and 가 보니까.
• 보다 means "try" or "look and see". It does not mean "because".
• The second clause states the finding, usually in the past.
• The second clause is not a command or a suggestion.

Listen to two model sentences.

The next section defines the pattern.

What Does -아/어 보니(까) Grammar Mean?

-아/어 보니(까) means "when I tried it, I found out". A connective ending is a word ending that joins one clause to the next. This one tells the listener, "I did something to test it or to see it, and here is what I found."

The pattern has two jobs for the verb 보다. First, 보다 is the "try" helper in -아/어 보다, as in 먹어 보다 ("try eating"). Second, the ending -(으)니까 here marks a discovery, as in "looking, I found". Put together, 먹어 보니까 means "having tried eating, I found...". The verb can also mean going or opening to look, as in 가 보니까 ("when I went there and looked").

Here are two glossed examples.

Revised Romanization (RR) is the national system for writing Korean in the Latin alphabet. It is shown here only as a learning aid.

The next section shows how to build the form.

How Do You Form -아/어 보니(까)?

Take the dictionary form, remove 다 to get the stem, and add the 아/어 form of the stem. This is the same form you use in -아요/어요, without the 요. Then add 보니까. The stem is the verb without its dictionary ending -다. For 먹다 the stem is 먹.

Vowel harmony decides between 아 and 어. If the last vowel of the stem is ㅏ or ㅗ, add 아. For any other vowel, add 어. For 하다 verbs, use 해.

When the stem already ends in ㅏ, the 아 merges with it, so 가 + 아 is just 가. In the same way, 오 + 아 becomes 와, and 하 + 여 becomes 해. RR shows the aspiration in verbs, so 도착해 is dochakae.

Stems Ending in a Vowel

Vowel stems either merge or stay the same. 가 stays 가, 오 becomes 와, 보 becomes 봐, and 쓰 becomes 써. The ending 보니까 follows with a space.

Stems Ending in a Consonant

Consonant stems add 아 or 어 by vowel harmony: 먹어, 앉아, 입어, 읽어. The 어 or 아 is a helping syllable that lets the final consonant move to the next syllable in speech, as in 먹어 [머거].

Irregular Stems

Irregular stems follow the same changes as in the polite form. An irregular stem is one that changes its shape before an ending that begins with a vowel.

The pattern is for verbs. Adjectives do not normally take it, since you cannot "try" a state. The next section builds a full sentence.

Worked Example: Building 이 음식을 먹어 보니까 맛있었어요

Say that you tried a dish and found it tasty. Follow five steps.

1. Write the action. "I eat this dish" is 이 음식을 먹어요 in the polite style.
2. Find the stem. The dictionary form is 먹다, so the stem is 먹.
3. Choose 아 or 어. The last vowel of 먹 is ㅓ, so use 어: 먹어. Add 보니까: 먹어 보니까. Take away the polite ending 요.
4. Write the finding. "It was tasty" is 맛있었어요. The past form shows that the tasting was done.
5. Join the two parts. 이 음식을 먹어 보니까 맛있었어요.

You'll know it worked when the first verb ends in 어 보니까 with nothing after it, and the polite ending appears only once, at the end. Spoken, it is [이 음시글 머거 보니까 마시써써요]. Try the same steps with "When I went there, nobody was there": 가다 gives 가 보니까, and 사람이 없었어요 follows.

The next section covers what can follow.

Which Tenses and Sentence Types Work with -아/어 보니(까)?

The first clause has no tense marker. You do not write 먹었어 보니까. The pattern already looks back at an action. The finding clause carries the time, and it is usually in the past, because the speaker is reporting what they saw.

Use the present only when the finding is still true now. The spoken forms are [여러 보니까 아무도 업써써요] for 열어 보니까 아무도 없었어요 and [사라 보니까 서우리 조아요] for 살아 보니까 서울이 좋아요.

The pattern reports something already found, so a prediction does not fit. Wrong: 먹어 보니까 맛있을 거예요. You also cannot follow it with a command or a suggestion. Wrong: 먹어 보니까 같이 먹어요. To give advice, use a reason instead: 맛있으니까 드세요.

Yes/no questions usually end with a rise. A wh-question puts the stress on the question word and often ends with a fall or a rise-fall, rather than a sharp final rise.

The next section compares -아/어 보니(까) with similar patterns.

How Is -아/어 보니(까) Different from Nearby Patterns?

Four patterns share the sound 보니(까) or the idea of a finding. Each has its own job.

The main question is about time. In -아/어 보니(까), the action is done once, and the finding follows right away. In -다 보니(까), time passes, and the result builds up. For -(으)니까, nothing is found out. The speaker gives a reason, and so a command can follow: 맛있으니까 드세요.

The pattern -았/었더니 also reports what the speaker noticed. It is closer to "cause and effect": you did something, and a result followed. -아/어 보니(까) is closer to "trial and finding". The two can overlap, so many speakers use either one.

The next section covers set phrases and edge cases.

Variations and Edge Cases of -아/어 보니(까)

알고 보니: It Turned Out

The phrase 알고 보니 is a fixed phrase that means "it turned out" or "when I found out". 알고 보니 친구의 동생이었어요 means "It turned out to be my friend's younger sibling." It uses -고 보니, not -아/어 보니, but it has the same discovery feeling.

보니까 as "Judging By"

The literal "see" meaning of 보다 gives a use without 아/어. 얼굴을 보니까 피곤해 보여요 means "Looking at your face, you seem tired." Here 보니까 stands for "seeing that".

-아/어 보면: If You Try

Change 니(까) to 면 and you get "if you try". 먹어 보면 알 거예요 means "If you try it, you will know." The 보니까 form looks back. The 보면 form looks forward.

보니 and 보니까

The 까 is optional. 가 보니 and 가 보니까 mean the same. The short form is a little more written.

Spacing

This site writes 아/어 보니까 with a space. The attached form 먹어보니까 appears often online.

The next section lists the mistakes that appear most often.

What Mistakes Do Learners Make with -아/어 보니(까)?

Learners make six predictable mistakes. Each has a reason and a fix.

Learners often read 보니까 as "because". Wrong: 먹어 보니까 같이 먹어요 when you mean "Since it is tasty, let's eat together". Right: 맛있으니까 같이 먹어요. Fix: here 보니까 means "having tried". For a reason, use -(으)니까 on its own.

Learners often leave out 아/어. Wrong: 먹 보니까 맛있었어요. Right: 먹어 보니까 맛있었어요. Fix: the pattern needs the 아/어 form of the stem.

Learners often pick the wrong vowel. Wrong: 먹아 보니까 and 앉어 보니까. Right: 먹어 보니까 and 앉아 보니까. Fix: use 아 after ㅏ or ㅗ, and 어 after other vowels.

Learners often put a prediction after it. Wrong: 먹어 보니까 맛있을 거예요. Right: 먹어 보니까 맛있었어요. Fix: the pattern reports a finding that has already been made.

Learners often use -다 보니(까) for one try. Wrong: 한 번 먹다 보니까 맛있었어요. Right: 먹어 보니까 맛있었어요. Fix: -다 보니(까) needs time passing. For one trial, use -아/어 보니(까).

Learners often put a tense inside. Wrong: 먹었어 보니까 맛있었어요. Right: 먹어 보니까 맛있었어요. Fix: the first clause has no tense. The finding clause shows the time.

The next section gives you practice.

Practice and Answers

Do the four tasks, then compare with the key.

Task 1: add -아/어 보니까. Write the form of each verb.

1. 먹다 (eat)
2. 가다 (go)
3. 하다 (do)
4. 듣다 (listen)
5. 오다 (come)
6. 쓰다 (use, write)

Task 2: join the sentences with -아/어 보니까. Write one sentence for each pair.

1. 저는 이 옷을 입어요. / 잘 맞아요.
2. 저는 문을 열어요. / 아무도 없었어요.
3. 저는 일어나요. / 벌써 아침이었어요.

Task 3: fix the error. Each sentence has one mistake. Rewrite it correctly.

1. 먹 보니까 맛있었어요.
2. 먹아 보니까 맛있었어요.
3. 먹어 보니까 드세요. (meaning: Because it is tasty, please eat.)

Task 4: write your own. Write one sentence about a new food you tried, and one about a place you visited.

Answer key

1. (1) 먹어 보니까 (2) 가 보니까 (3) 해 보니까 (4) 들어 보니까 (5) 와 보니까 (6) 써 보니까
2. (1) 저는 이 옷을 입어 보니까 잘 맞아요. (2) 저는 문을 열어 보니까 아무도 없었어요. (3) 저는 일어나 보니까 벌써 아침이었어요.
3. (1) 먹어 보니까 맛있었어요. (2) 먹어 보니까 맛있었어요. (3) 맛있으니까 드세요.
4. Sample answers: 김치를 먹어 보니까 생각보다 맛있었어요. 부산에 가 보니까 바다가 정말 예뻤어요. Any pair is correct if the first verb ends in 아/어 보니까 and the second clause reports a finding.

If task 1 was correct, you have the formation rule. If task 3 was hard, check the vowel of the stem and whether the second clause is a finding and not a request. The next section points you to what comes after this lesson.

What Should You Learn after -아/어 보니(까) Grammar?

After -아/어 보니(까), review -다 보니(까) to keep "one try" and "over time" apart, and -(으)니까 for reasons. Later, -았/었더니 gives another way to report what you noticed.

For a wider view, the parent page Time and Sequence lists every time connector in this group. To plan by level, use Intermediate Grammar.

This lesson covers -아/어 보니(까) in the polite, casual and formal styles. It does not cover every written variation. About this page. Last updated 2026-10-09. Revised Romanization follows the national rules and is shown only as a learning aid.

Frequently Asked Questions

What Does -아/어 보니(까) Mean?

-아/어 보니(까) means "when I tried it, I found out". The first clause is an action done to test or to see. The second clause tells what the speaker found. 먹어 보니까 맛있었어요 means "When I tried it, it tasted good." The same pattern also covers going somewhere and finding something there.

How Do I Attach -아/어 보니(까) to a Verb or Adjective?

Use verbs. Remove 다 to get the stem and add 아 after ㅏ or ㅗ, otherwise 어. 먹다 becomes 먹어 보니까, 앉다 becomes 앉아 보니까, and 하다 becomes 해 보니까. Vowel stems contract: 가다 becomes 가 보니까, 오다 becomes 와 보니까. Write a space before 보니까.

Can -아/어 보니(까) Be Used in the past Tense?

The first clause does not take a past marker, so you do not write 먹었어 보니까. The pattern already looks back on an action. The finding clause is usually in the past, as in 가 보니까 사람이 없었어요. A present finding is possible if it is still true, as in 입어 보니까 잘 맞아요.

Is -아/어 보니(까) Used in Speech or Only in Writing?

It is used in both. It is common in conversation, reviews, blogs and stories, whenever the speaker reports a first-hand experience. The short form 보니 is a little more written. The longer 보니까 is more spoken. Both work in polite, casual and formal speech, since the final verb sets the style.

What Is the Most Common Mistake with -아/어 보니(까)?

Learners read 보니까 as "because". It is not a reason here. 먹어 보니까 means "having tried it", and it cannot lead into a command such as 같이 먹어요. For a reason, use -(으)니까 alone, as in 맛있으니까 먹어요. Another slip is leaving out 아/어, as in 먹 보니까.

What Is the Difference between -아/어 보니(까) and -다 보니(까)?

-아/어 보니(까) reports a finding after one try or one look. -다 보니(까) reports a result that grew while you kept doing something over time. 먹어 보니까 맛있었어요 is "I tried it, and it was good". 공부하다 보니 재미있어졌어요 is "As I kept studying, it became fun".

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