Yesterday my wife and I went to a takeaway food shop in suburban Sydney called 이레 (transliterated as Irae outside and Irea on the server's aprons). This word was not on my translator app or Google Translate. I asked my (Korean, university-educated) wife and she had to think for a few moments before she tentatively said 'seven days'. I know 하루 and 이틀, so I asked if it was connected to those, and she said yes.

One of my Korean textbooks gives 하루, 이틀, 사흘 and 나흘 in the context of a medical appointment (instructions for taking medicine), but comments that the last two are usually replaced by 3일 and 4일 (presumably pronounced sam-il and sa-il).

What is the origin of the 하루, 이틀 ... series, and how often are those terms used, and in which contexts? They appear to be related (more or less clearly, in some cases) to the Korean numbers, but the second syllable is inconsistent. Is there a pattern I'm missing? Do I really have to learn the numbers between 3 and 6, 8 and 10, or are they too rarely used?

(I later found 이레 in the biggest Korean/English dictionary we have. I found some related information on this SE (here) and on Quora (here).)

2 Answers 2


You may want to memorize at least up to 엿새 (six days), and maybe 열흘 (ten days). There aren't really much more. I learned 열하루, 열이틀, 열사흘, 열나흘, and 보름 (fifteen days) at school, but they're very rarely used.

I think almost all native Koreans would be able to understand phrases like "그 이후 이레가 지났다. (Seven days have passed since.)" On the other hand, most people will simply use 7일 or 1주일 these days, and seeing just the word "이레" (without any context whatsoever) would probably throw them off, because it's such a rarely used term.


(1) In math book, 1 2 3 4 5 ... -> 일 이 삼 사 오 ...

10 십 20 이십 100 백 1000 천

For instance, 12 십이, 12.017 십이점 일칠, 0.1 영점 일 and 1002 천이

(2) Counting way : 하나 둘 셋 넷 다섯 여섯 일곱 ...

10 열 11 열하나 20 스물 30 서른 40 마흔 100 백 1000 천 1111 천백열하나

What is old ? 나이가 어떻게 되니 ? 33. 서른 셋입니다.

(3) Order : 첫번째 두번째 세번째 네번째 다섯번째 여섯번째 일곱번째

(or 첫째 둘째 셋째 넷째 다섯째 여섯째 일곱째)

10 열번째 121 백 스믈 한번째 122 백 스물 두번째

What do your second son ? 둘째 아들은 뭐해 ? He is a doctor.

(4) Mixed : What time is it now? 11:12 열한시 십이분 10:10 열시 십분 03:03 세시 삼분

(5) 하루 이틀 사흘 나흘 :

From here to Seoul, it takes 48 hours by train. 서울까지는 기차로 이틀걸린다.

(6) 날짜 : March 6 삼월 육일 (or 삼월 초엿새날)

March 5 (삼월 초 닷새)

March 7 삼월 칠일 (or 삼월 (초)이레(날))

December 7 십이월 칠일

In the above, ( )-expression is heard sometimes. For instance, her birth day is April 1 (2) according to the lunar calendar. 그 애 생일은 사월 초 하루 (초 이튿날)

In further, these expression are usually used by older people.

  • 2
    According to the standard Korean grammar, you have to always space before a 번째: 첫번째 must be 첫 번째, and so on. Commented Mar 18, 2018 at 23:29

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