Korean numbers explained: native vs Sino-Korean and when to use each

TUREFF• •0

Korean has two complete sets of numbers, and almost every learner trips over them at first. The good news is that the rule for choosing between them is fairly consistent: one set is for counting things, the other is for measuring, dates and money. Once that clicks, the rest is practice.

The two systems

Native Korean numbers are the older, purely Korean words:

하나 hana (1), 둘 dul (2), 셋 set (3), 넷 net (4), 다섯 daseot (5)
여섯 yeoseot (6), 일곱 ilgop (7), 여덟 yeodeol (8), 아홉 ahop (9), 열 yeol (10)
스물 seumul (20), 서른 seoreun (30), 마흔 maheun (40), 쉰 swin (50)

Sino-Korean numbers come from Chinese:

일 il (1), 이 i (2), 삼 sam (3), 사 sa (4), 오 o (5)
육 yuk (6), 칠 chil (7), 팔 pal (8), 구 gu (9), 십 sip (10)
백 baek (100), 천 cheon (1,000), 만 man (10,000)

Sino-Korean numbers are built like a calculator: 십일 (11) is ten-one, 이십 (20) is two-ten, 삼백오십 (350) is three-hundred-five-ten. Native numbers only go up to 99 in everyday use; above that, everyone switches to Sino-Korean.

Which one to use

Counting things and people: native. Three coffees, two people, five bottles.
Age in everyday speech: native, with 살. I am 25 is 스물다섯 살.
Hours on the clock: native, with 시. Three o'clock is 세 시.
Minutes and seconds: Sino-Korean, with 분 and 초. 3:30 is 세 시 삼십 분.
Money: Sino-Korean, with 원. 5,000 won is 오천 원.
Dates: Sino-Korean. 9 October is 시월 구일.
Phone numbers, floors, room and bus numbers: Sino-Korean. Zero in a phone number is usually 공.

The clock is the classic trap: hours native, minutes Sino-Korean, in the same phrase.

Counters you will use every day

Korean usually puts a counter word after the number, a bit like "three cups of" or "two pieces of".

개 for general things: 사과 세 개 (three apples)
명 for people: 두 명 (two people); in restaurants you will hear this constantly
살 for age: 열 살 (ten years old)
시 for o'clock: 한 시 (one o'clock)
분 for minutes: 십오 분 (fifteen minutes)
원 for won: 만 원 (10,000 won)

Others worth learning soon: 잔 (cups or glasses), 병 (bottles), 권 (books), 마리 (animals), 장 (flat things like tickets or photos), 번 (times, as in "twice").

The shortened forms

Native numbers 1 to 4 and 20 change shape before a counter:

하나 becomes 한: 한 개, 한 시
둘 becomes 두: 두 명
셋 becomes 세: 세 시
넷 becomes 네: 네 개
스물 becomes 스무: 스무 살

So you say 한 명, never 하나 명. This applies inside larger numbers too: 21 years old is 스물한 살.

Money and the 만 problem

Korean groups big numbers by ten thousand, not by thousand. 10,000 is 만, 100,000 is 십만, 1,000,000 is 백만. When you see a price like 35,000원, think "three-man-five-thousand": 삼만 오천 원. It takes a while to stop converting in your head; reading price tags aloud in a shop is the fastest way to get there.

Common mistakes

Using Sino-Korean for hours: 삼 시 sounds wrong; it is 세 시.
Forgetting the short forms: 하나 개 instead of 한 개.
Counting people with 개. Use 명, or the politer 분 when talking about guests or customers.
Months with irregular forms: June is 유월 and October is 시월, not 육월 and 십월.
Reading a phone number with native numbers. It is Sino-Korean throughout, and 0 is usually said 공.

Age, briefly

Since 2023 South Korea has officially used international age (counted from birth) in law and administration, replacing the older system in which people added a year every New Year. In conversation you may still meet the old way of counting, so if a number sounds a year or two high, that is probably why.

How to practise

Read every price, bus number and clock you see aloud, in the right system.
Order in a café using 개 or 잔 and a native number.
Say today's date and time in Korean each morning.

What number habit still catches you out? Share it, or ask about a counter, in the comments.