Korean Number Systems: Native Korean vs Sino-Korean Numbers
Korean uses 하나, 둘, 셋 in some contexts and 일, 이, 삼 in others. Learn which system to use for counters, age, time, dates, money, and phone numbers.
Two words for three
Korean does not have one word for “three.” It has 셋 and 삼, and they are not style variants. They belong to two counting systems that split the language between them.
The older set is native Korean: 하나, 둘, 셋, 넷, 다섯, 여섯, 일곱, 여덟, 아홉, 열 (hana, dul, set, net, daseot, yeoseot, ilgop, yeodeol, ahop, yeol). You use it for things you can point at one by one, for age in 살, and for the hour on a clock.
The other set came in with Chinese characters: 일, 이, 삼, 사, 오, 육, 칠, 팔, 구, 십 (il, i, sam, sa, o, yuk, chil, pal, gu, sip). Dates, money, phone digits, addresses, and minutes run on this set. So do 백, 천, and 만 once the number leaves the small range.
Why two systems
That is the split. Native Korean kept the work of counting discrete things. The Sino-Korean set took the work of measuring, dating, and listing digits. Neither set is “formal” or “casual.” A shop receipt and a child’s age just live in different systems.
In a sentence
사과가 세 개 있어요.
sagwaga se gae isseoyo — There are three apples.
사과가 is new information — you are pointing the apples out. That is 이/가. The number is native, already shortened: 셋 becomes 세 before a counter. 삼 개 is the wrong set in that slot.
하나예요.
hanayeyo — It’s one.
After a vowel, the copula is -예요. After a batchim it is -이에요. 이다 attaches to the number the way it attaches to any noun.
고유어는 물건을 셀 때 써요. 한자어는 날짜와 돈에 써요. That 은/는 vs 이/가 is doing the contrast work: one set, as opposed to the other.
On a clock
The place both systems sit in one sentence is a clock. Hours take native Korean. Minutes take Sino-Korean. 세 시 삼십 분 is 3:30, and the switch happens between 시 and 분. That is the next lesson. Counters are the lesson after this one: what attaches to the number, and why 하나 becomes 한.
If you remember only one test: ask whether you are counting objects you could pick up, or reading a calendar, a price, or a keypad. Objects go native. The rest go Sino-Korean. When both appear, as they do on a clock, each half of the sentence keeps its own set.
Common questions
Do I really need both from week one?
You need both eventually, but you can learn them in small groups. Clock time is a useful early example: native 세 시 with Sino-Korean 삼십 분. Then add the sets used for counters, dates, money, and phone digits.
What happens after 99?
Hundreds, thousands and 만 are Sino-Korean — 백, 천, 만. A leftover native digit can still sit on the end: 백한 개 is 101 of something. You do not invent a native word for 100.
Is 이 the same 이 as 'this'?
Same spelling, different word. Number 이 is Sino-Korean two. Demonstrative 이 is 'this.' Stress and what follows will tell them apart; 이 분 is 'two minutes' or, with a pause and a person, 'this person' — context does the work.
Can I pick one set and stick to it?
Not usually. Native numbers are common with things counted one by one and with hours; Sino-Korean numbers are common with dates, money, phone digits, and minutes. Some expressions vary, so learn the counter or unit with its usual number set.
Practice & questions
Try a sentence with an expression from this lesson, or ask about anything you are still unsure of.
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