Numbers in Korean

How numbers work in Korean

Korean has two number systems. The Sino-Korean numbers 일, 이, 삼, 사, 오, 육, 칠, 팔, 구, 십 are used for prices, dates, phone numbers, minutes and anything from 100 up. The native Korean numbers 하나, 둘, 셋, 넷, 다섯 … 열 are used for counting things and people, for age and for the hour on the clock. They only go up to 99.

The Sino-Korean system is completely regular: 십일 is 'ten one' (11), 이십 'two ten' (20), 이십일 'two ten one' (21). For 10, 100 and 1,000 you just say 십, 백, 천, without 일. Zero is 영, or 공 in phone numbers.

The native tens have their own words: 열 (10), 스물 (20), 서른 (30), 마흔 (40), 쉰 (50), 예순 (60), 일흔 (70), 여든 (80), 아흔 (90). Before a counter, 하나, 둘, 셋, 넷 and 스물 shorten to 한, 두, 세, 네 and 스무: 한 개, 두 사람, 스무 살.

Large numbers are grouped in fours: 10,000 is 만, 100,000 is 십만, a million 백만. With 만 the 일 is usually dropped.

Ordinals use the native numbers with 번째: 첫 번째 (first), 두 번째, 세 번째. With Sino-Korean numbers the prefix 제 is used: 제일 (number one).

Korean mixes both number systems when telling the time: the hour uses native numbers with 시 (세 시, 3 o'clock), the minutes use Sino-Korean numbers with 분 (십오 분, 15 minutes). Half is 반 and is added to the past hour: 세 시 반 is 3:30. With 전 (before) you can count back from the next hour: 네 시 십오 분 전.

Conversation uses the 12-hour clock; 오전 (a.m.) and 오후 (p.m.) go before the time. With the 24-hour clock, for example in timetables, the hour is read with Sino-Korean numbers too: 십사 시 이십 분.