Korean Counter Ju (주): How to Count Weeks in Korean

What you'll learn

• Count weeks from one to twelve with 주 and Sino-Korean numbers.
• Say "one week" with 일주일 and know when 주일 is used instead.
• Ask 몇 주 걸려요? ("how many weeks does it take?") and answer.
• Use 이번 주, 다음 주, 지난주 and 매주 for this, next, last and every week.
• Describe a course or a plan in weeks, such as 육 주 과정.
• Prerequisites: Sino-Korean numbers 1-12. Estimated time: 20 minutes.

Korean Counter Ju: the Essentials

The Korean counter ju (주) is the Sino-Korean word for "week" used as a counter, and it comes from the Chinese character 週 (cycle, week). It follows a Sino-Korean number: 이 주 (two weeks), 삼 주 (three weeks), 사 주 (four weeks). It measures a duration, which is a length of time, and it is not a day of the week or a date.

One week is a special case. The natural form is 일주일, written as one word, and 일 주 is rarely used. The syllables 주 and 일 in 일주일 combine as 일 (one) + 주일 (week), and that is why 이 주일, 삼 주일 and so on are all formed with the same noun. Standard pronunciation tenses the ㅈ after the ㄹ of 일, so 일주일 sounds like [일쭈일], and 육 주 sounds like [육쭈] for the same reason: a final ㄱ makes the next ㅈ tense. The spelling does not change.

The pairing of 주 with Sino numbers is no accident, and the next section explains it.

Which Number System Does 주 Take?

주 takes Sino-Korean numbers as its standard form. Native numbers (한 주, 두 주) also occur in speech, but only in some phrases. Sino-Korean is the form you will see on schedules, forms and course pages, so it is the safe default.

Native forms sit in set phrases about duration. 한 주 동안 means "for a week" and 두 주 동안 "for two weeks". These are heard in conversation and in the news, and the Sino forms (일주일 동안, 이 주 동안) are equally correct. Standard written Korean mostly keeps Sino-Korean numbers with 주, which matches the wider split described in Sino vs native Korean numbers. The Sino numbers themselves are drilled in Sino-Korean numbers 1-100.

Expert insight: 이 주 can also mean "this week", because 이 is also the word for "this". Speakers avoid the clash by saying 이번 주 for "this week" and, when the meaning "two weeks" must be unmistakable, 이 주일 or 2주 (read 이 주). For one week, 일주일 동안 and 일주일간 are both fine.

A counter is only useful in a sentence, so the next section sets the grammar.

How Do You Use 주 in a Sentence?

To use 주 in a sentence, put the Sino number and 주 first, then add a time word such as 동안 (for), 전 (ago), 후 (later) or 에 (within, per). The week phrase works like an English time expression and needs no plural ending.

• 이 주 동안 한국에 있을 거예요. "I will be in Korea for two weeks."
• 삼 주 전에 시작했어요. "I started three weeks ago."
• 사 주 후에 시험이 있어요. "The exam is in four weeks."
• 일주일에 두 번 운동해요. "I exercise twice a week."

In the table, 전 and 후 carry the particle 에 (삼 주 전에, 사 주 후에), which marks the point in time. Without it, the phrase becomes a noun: 삼 주 전 사진 means "a photo from three weeks ago".

The counter also joins numbers with conjunctions: 이삼 주 ("two or three weeks"), 삼사 주 ("three or four weeks"), 한두 주 ("a week or two"). The first two use Sino pairs, and the last uses a native pair for a loose, spoken sense. These approximations are natural in plans because nobody knows the exact length.

How Do You Ask How Many Weeks?

Ask 몇 주 걸려요? to ask how many weeks something takes. 몇 is the question word "how many", and 걸리다 means "to take (time)". The answer repeats the counter: 삼 주 걸려요.

The pronunciation is [멷쭈], because the final ㅊ of 몇 turns into [ㄷ] and the ㅈ after it becomes tense. If you answer with a number you do not need to say more: 이 주요 is a polite short reply ("Two weeks.").

Which Calendar Words Use 주?

Four calendar words use 주 without a number: 이번 주, 다음 주, 지난주 and 매주. They point to a particular week or to all weeks, and they are among the most useful time words you can learn.

The spacing follows the standard spelling: 지난주 is written as one word, and 이번 주 and 다음 주 are two words. Compare the month words 지난달 and 다음 달 in the lesson on the 달 and 개월 counters, where the same split appears. To attach a weekday, put the week word first: 다음 주 월요일 is "next Monday", and the names of the days are in days of the week in Korean.

• 이번 주에 바빠요. "I am busy this week."
• 다음 주 금요일에 만나요. "Let's meet next Friday."
• 지난주에 이사했어요. "I moved last week."
• 매주 토요일에 한국어를 공부해요. "I study Korean every Saturday."

These words name weeks relative to now, and they give the grammar a calendar to hang on. The next section shows durations where weeks matter most.

Where Do Weeks Appear in Plans?

Weeks appear in the time spans that people plan around: courses, projects, holidays, medical care and pregnancy. In each case the Sino counter 주 stands after a number, and the phrase works as a label.

The word 정도 means "about" and follows the counter phrase. It softens an exact length: 삼 주 정도 means "about three weeks". For a range, use two numbers: 이삼 주 정도 is "about two or three weeks".

A last use is the rate. 주 followed by a number and another counter gives "per week": 주 오 일 근무 is "five days of work per week", and 주 일 회 on a schedule means "once per week". The wording 주 사십 시간 is "forty hours per week". The phrase 격주 means "every other week", as in 격주로 모여요 ("We meet every other week"). In everyday speech, Koreans use the 일주일에 pattern from the sentence table instead.

Two Short Conversations

At a language school. A student asks how long a course runs.

The dialogue uses 주 for the course (십 주), 일주일에 for the rate, and 다음 주 for the start. The class count 사 일 is days, and it uses the Sino 일 counter from the 일 counter.

At the doctor's. A patient asks how long recovery takes.

Both numbers are Sino because they measure time. The speaker adds 정도 to soften the first number, which is the natural way a professional gives an estimate.

Worked Example: Planning a Trip in Weeks

A learner describes a plan in four sentences.

1. 다음 주에 한국에 가요. "I am going to Korea next week."
2. 삼 주 동안 있을 거예요. "I will stay for three weeks."
3. 첫 주에는 서울에 있고, 나머지 이 주는 부산에서 지낼 거예요. "In the first week I will be in Seoul, and I will spend the remaining two weeks in Busan."
4. 일주일에 두 번 한국어 수업을 들을 거예요. "I will take Korean lessons twice a week."

The checkpoint: 다음 주 is a calendar word and takes no number, 삼 주 is a counted span, 첫 주 is an ordinal ("first week"), and 일주일에 두 번 is a rate. If one of these four feels shaky, the mistakes below point to the cause.

Common Mistakes and Fixes

• 세 주 in formal writing → 삼 주. Native 세 주 is heard in speech, but 삼 주 is the standard form.
• 일 주 → 일주일. One week is the noun 일주일.
• 지난 주 → 지난주. 지난주 is one word.
• 이번주 → 이번 주. 이번 주 is two words.
• 이 주 마다 → 이 주마다. The particle 마다 ("every") attaches to the word before it: 이 주마다 or 이 주일마다 is "every two weeks".
• 매 주 → 매주. 매주 is one word.

Learners often assume that 주 and 주일 are two different counters. Actually they are the same word in a short and a long form, and the choice is mostly a matter of rhythm: 이 주 sounds lighter, 이 주일 sounds more formal. The practice set tests five of these points.

Practice Set

Say each answer aloud, then check below.

1. "three weeks"
2. "one week"
3. "How many weeks does it take?"
4. "next week"
5. Fix the error: 지난 주
6. Fix the error: 일 주 동안
7. "a six-week course"

Answers: 1. 삼 주. 2. 일주일. 3. 몇 주 걸려요? 4. 다음 주. 5. 지난주. 6. 일주일 동안. 7. 육 주 과정.

If item 2 or 6 tripped you, reread the essentials; if item 5 did, return to the calendar-words section.

What This Lesson Does Not Cover

This lesson covers counting weeks and the calendar words built on 주. It does not teach the days of the week, hours and minutes, or the counters for days, months and years; each has its own lesson. It also leaves out the ordinal forms for weeks (첫째 주, 둘째 주), which belong with ordinals. The guidance on 한 주 and 두 주 describes tendencies in standard Seoul Korean, and speakers differ.

What to Learn Next

Continue with months in the 달 and 개월 counters, or go back to days in the 일 counter. For weekday names, see days of the week in Korean, and for words such as 오늘 and 내일, see Korean time expressions. The Time Counters section lists every period counter. With the Korean counter ju in place, plans from one week to a quarter of a year are within reach.

Frequently Asked Questions

Is it 이 주 or 두 주? The standard form is 이 주, with the Sino-Korean number. 두 주 is also heard in speech, especially in phrases like 한 주 동안 ("for a week"), but 이 주 and 이 주일 are safer in writing and on forms. The week names 이번 주 and 다음 주 do not take numbers at all.

What is 주일? 주일 (週日) is the longer noun form of "week". 이 주일 and 삼 주일 mean exactly the same as 이 주 and 삼 주, and one week is 일주일. In Christian churches you also hear 주일 (主日), a different word that means Sunday, the day of worship, so the context decides which meaning you hear.

How do I say next week in Korean? Say 다음 주 for next week, 이번 주 for this week and 지난주 for last week. Note the spacing: 이번 주 and 다음 주 are two words, but 지난주 is one word. For "a week from now", say 일주일 후에, and for "the week after next", say 다다음 주.

How do I say "every week" in Korean? Say 매주, as in 매주 일요일에 운동해요 ("I exercise every Sunday"). For "once a week", say 일주일에 한 번. For "every other week", say 격주로, which is written as one word. On schedules you may see 주 일 회, where 회 means "times", for "once per week".

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