Key facts
- This page lists 16 patterns, and each has its own lesson.
- The list runs from A2 to B2 in our own placement, as a guide for planning your study.
- Start with -아/어서, then -(으)니까 and -기 때문에.
- Comparison pages cover the most confusable pairs.
Listen to the most common pattern in a sentence.
The next section explains what these patterns have in common.
What Are the Korean Because Grammar Patterns?
A reason pattern joins two clauses. The first clause gives the cause, and the last clause gives the result. 비가 와서 집에 있었어요 means "It rained, so I stayed home." The cause comes first in Korean, while English often puts the result first: "I stayed home because it rained."
The patterns differ in four ways.
- Feeling. Some are neutral. 덕분에 is grateful. 탓에 blames. -(으)ㄹ까 봐 worries.
- Tense. Some allow a past marker inside (-(으)니까), and some do not (-아/어서).
- What can follow. Some allow a command or suggestion after them, and some do not.
- Register. Some are spoken (-아/어 가지고, -길래), and some are formal and written (-(으)므로).
Each lesson teaches the rule for its pattern, with audio examples, common mistakes and a short practice set.
Which Pattern Should You Learn First?
Learn in this order. The first three cover most everyday reasons.
| Level | Patterns | What you gain |
|---|---|---|
| A2 | -아/어서, -(으)니까, -기 때문에 | neutral, speaker's, and firm reasons |
| B1 | 덕분에, -거든, -아/어 가지고, -(으)ㄹ까 봐 | thanks, an added reason, casual speech, worry |
| B2 | -(으)므로, -느라고, -는 바람에, 탓에, -고 해서, -길래, -(으)ㄴ/는 이상, -(으)ㄴ/는 만큼, -는 통에 | formal writing, blame, and finer shades |
Begin with -아/어서 before the rest. It is the most common pattern, and learning it shows you the limits that the others work around.
The Patterns, Grouped by Level
Beginner Patterns (A2)
-아/어서 gives a plain reason, and it also means "and then" between two connected actions. It takes no tense inside, and no command after a reason. 비가 와서 집에 있었어요. (It rained, so I stayed home.)
-(으)니까 gives the speaker's own reason. It can take a past marker, and it can lead into a command or a suggestion. It also has a "discovery" sense. 비가 오니까 우산을 가져가세요. (It's raining, so take an umbrella.)
-기 때문에 states a reason firmly or formally. It can end a sentence with 때문이다. 바쁘기 때문에 못 갔어요. (I could not go because I was busy.)
Intermediate Patterns (B1)
-(으)ㄴ/는 덕분에 means "thanks to" and needs a good result. 선생님 덕분에 합격했어요. (Thanks to my teacher, I passed.)
-거든 gives a reason that the listener may not know, often at the end of a sentence as -거든요. 저는 못 가요. 일이 많거든요. (I can't go. I have a lot of work.)
-아/어 가지고 is a casual spoken "because" or "and then". 길이 막혀 가지고 늦었어요. (The road was jammed, so I was late.)
-(으)ㄹ까 봐 means "worried that" or "in case". 늦을까 봐 택시를 탔어요. (I took a taxi in case I was late.)
Advanced Patterns (B2)
Nine lessons cover the B2 patterns. Two of them appear in the sentences below.
- -(으)므로 (therefore).
- -느라고 (because I was busy doing X).
- -는 바람에 (because of an unexpected event). 길이 막히는 바람에 늦었어요. (A traffic jam made me late.)
- -(으)ㄴ/는 탓에 (because of, with blame). 늦게 일어난 탓에 지각했어요. (I was late because I got up late.)
- -고 해서 (partly because).
- -길래 (because, after noticing something).
- -(으)ㄴ/는 이상 (now that, since).
- -(으)ㄴ/는 만큼 (to the extent that).
- -는 통에 (because of a commotion).
How Do You Choose between Look-Alike Patterns?
Start with what you want to say, and use the table to find the pattern.
| You want to say | Use | Level |
|---|---|---|
| a plain reason, or "and then" | -아/어서 | A2 |
| a reason, then a command or suggestion | -(으)니까 | A2 |
| a firm, formal reason | -기 때문에 | A2 |
| thanks to someone | 덕분에 | B1 |
| a reason the listener may not know | -거든 | B1 |
| worry about something that might happen | -(으)ㄹ까 봐 | B1 |
| a formal "therefore" in writing | -(으)므로 | B2 |
| a bad result from an unexpected event | -는 바람에 | B2 |
| a bad result from being busy | -느라고 | B2 |
| blame | 탓에 | B2 |
The look-alike you meet first is -아/어서 versus -(으)니까. The key difference: -아/어서 cannot take a command or suggestion after the reason, and it takes no tense inside. -(으)니까 can do both. So 비가 오니까 우산을 가져가세요 is correct, and 비가 와서 우산을 가져가세요 is not natural. Read the side-by-side page: -아/어서 vs -(으)니까.
The other pages to keep close are -(으)니까 vs -기 때문에 and -기 때문에 vs -아/어서. For the B2 pairs, read -(으)ㄴ/는 덕분에 vs -(으)ㄴ/는 탓에 and -느라고 vs -는 바람에.
Where Can You Practise?
Each lesson includes practice tasks with an answer key and a short quiz, so practise right after you read. A good routine is to learn one pattern, then write two original sentences about your own day. Next, open the comparison page for that pattern, and check which of its look-alikes you mix up.
To plan a longer path, use the level lists: Beginner Grammar and Intermediate Grammar. The B2 patterns are also in Advanced Grammar.
What Does This Section Not Cover?
This page covers patterns that give a reason or a cause. Other connector groups have their own pages in Korean Connectors: And / But Connectors, Conditions (If), Time and Sequence, Purpose and Intention and Contrast and Concession.
Particles, tenses and speech levels have their own sections too. For the topic and subject particles, see Korean particles. For tense questions, such as why -아/어서 takes no past marker, see Korean tenses. For polite and formal endings, see Korean speech levels. The wider grammar hub is Korean Grammar.
About this page. Last updated 2026-10-09. The Korean examples are written with plain explanations and Revised Romanization is a learning aid only.
Frequently Asked Questions
What Are the Korean Because Grammar Patterns?
They are connecting endings and phrases that give a reason or cause, such as -아/어서, -(으)니까, -기 때문에, 덕분에 and 탓에. Each links two clauses, and each has its own tone, tense rules and sentence-type limits. This page lists 16 patterns and links to every lesson.
Which Pattern Should I Learn First?
Learn -아/어서 first. It is the most common everyday reason and also gives "and then". Next learn -(으)니까, which handles reasons before commands and suggestions, and -기 때문에, the firm and formal option. After those three, choose by need: thanks, blame, worry, or a formal written style.
How Do I Know Which Pattern Fits My Sentence?
Ask three questions. Do you need a command or suggestion after the reason? Then use -(으)니까. Is the result good or bad? Use 덕분에 for good and 탓에 or 는 바람에 for bad. Is the style formal and written? Use -(으)므로 or -기 때문에. Otherwise -아/어서 is the safe default.
Are These Patterns on the TOPIK Exam?
The common ones appear in everyday TOPIK reading and listening material, and the formal written ones appear at the higher levels. We place A2 patterns with TOPIK I preparation and B1 to B2 patterns with TOPIK II preparation, as a guide. Official exam information is at topik.go.kr. TOPIK does not publish a grammar list by level, so check your own textbook or course as well.
Where Are the Comparison Pages?
Each lesson has a "different from" section with a table for its closest look-alike. Longer side-by-side pages cover the pairs learners confuse most: -아/어서 versus -(으)니까, -(으)니까 versus -기 때문에 and -기 때문에 versus -아/어서. Pages for 덕분에 versus 탓에 and -느라고 versus -는 바람에 cover two more pairs.