Why Korean Has Two Number Systems
Korean uses two completely separate number systems — and knowing when to use which is one of the trickiest parts of learning Korean. This isn't just an academic distinction: using the wrong system in everyday situations will confuse native speakers.
Sino-Korean numbers (한자어 숫자) are derived from Chinese characters and used for dates, money, phone numbers, and counting above 100.
Native Korean numbers (고유어 숫자) are the original Korean counting words, used for counting objects (with counters), telling time (hours), and ages.
Sino-Korean Numbers (일, 이, 삼...)
| Number | Sino-Korean | Romanization |
|---|---|---|
| 0 | 영 / 공 | yeong / gong |
| 1 | 일 | il |
| 2 | 이 | i |
| 3 | 삼 | sam |
| 4 | 사 | sa |
| 5 | 오 | o |
| 6 | 육 | yuk |
| 7 | 칠 | chil |
| 8 | 팔 | pal |
| 9 | 구 | gu |
| 10 | 십 | sip |
| 100 | 백 | baek |
| 1,000 | 천 | cheon |
| 10,000 | 만 | man |
Building Sino-Korean Numbers
Sino-Korean numbers follow a logical pattern similar to Chinese:
11: 십일 (sip-il) = 10+1 | 25: 이십오 (i-sip-o) = 2×10+5 | 100: 백 (baek) | 234: 이백삼십사 (i-baek-sam-sip-sa) = 2×100+3×10+4
When to Use Sino-Korean
Dates: 2026년 6월 23일 (i-cheon-i-sip-yung-nyeon yu-wol i-sip-sam-il)
Money: 5,000원 (o-cheon-won)
Phone numbers: 010-1234-5678 (gong-il-gong il-i-sam-sa o-yuk-chil-pal)
Minutes: 30분 (sam-sip-bun)
Months: 6월 (yu-wol) = June
Floor numbers: 3층 (sam-cheung) = 3rd floor
Numbers above 99
Native Korean Numbers (하나, 둘, 셋...)
| Number | Native Korean | Modified Form* | Romanization |
|---|---|---|---|
| 1 | 하나 | 한 | hana / han |
| 2 | 둘 | 두 | dul / du |
| 3 | 셋 | 세 | set / se |
| 4 | 넷 | 네 | net / ne |
| 5 | 다섯 | — | daseot |
| 6 | 여섯 | — | yeoseot |
| 7 | 일곱 | — | ilgop |
| 8 | 여덟 | — | yeodeol |
| 9 | 아홉 | — | ahop |
| 10 | 열 | — | yeol |
| 20 | 스물 | 스무 | seumul / seumu |
| 30 | 서른 | — | seoreun |
| 40 | 마흔 | — | maheun |
| 50 | 쉰 | — | swin |
*Modified forms are used before counters. Numbers 1–4 and 20 have shortened forms when followed by a counter word.
When to Use Native Korean
Counting objects (with counters): 사과 세 개 (sagwa se gae) = three apples
Hours: 두 시 (du si) = 2 o'clock
Age (casual): 스물다섯 살 (seumul-daseot sal) = 25 years old
Counting people: 세 명 (se myeong) = three people
The Counter System
Korean uses counter words (similar to Chinese measure words) when counting objects. The counter changes based on what you're counting:
| Counter | Used For | Example |
|---|---|---|
| 개 (gae) | General objects | 두 개 (du gae) = 2 things |
| 명 (myeong) | People (polite) | 세 명 (se myeong) = 3 people |
| 마리 (mari) | Animals | 한 마리 (han mari) = 1 animal |
| 권 (gwon) | Books | 네 권 (ne gwon) = 4 books |
| 잔 (jan) | Cups/glasses | 두 잔 (du jan) = 2 cups |
| 병 (byeong) | Bottles | 세 병 (se byeong) = 3 bottles |
| 장 (jang) | Flat objects (paper) | 한 장 (han jang) = 1 sheet |
| 대 (dae) | Vehicles/machines | 두 대 (du dae) = 2 cars |
Telling Time: Both Systems Together
Telling time in Korean uses BOTH number systems simultaneously:
Hours = Native Korean | Minutes = Sino-Korean
3:45 = 세 시 사십오 분 (se si sasipo bun) — "se" (Native 3) + "si" (hour) + "sasipo" (Sino 45) + "bun" (minutes)
12:30 = 열두 시 삼십 분 (yeoldu si samsip bun)
Common Mistakes
Using Sino-Korean for hours: 삼 시 ✗ → 세 시 ✓ (hours always use Native Korean)
Forgetting modified forms: 하나 개 ✗ → 한 개 ✓ (1, 2, 3, 4, 20 shorten before counters)
Using Native Korean for money: 하나 천 원 ✗ → 일천 원 ✓ (money always uses Sino-Korean)
Quick Reference: Which System?
| Use Sino-Korean | Use Native Korean |
|---|---|
| Dates (년, 월, 일) | Hours (시) |
| Money (원) | Age (살) |
| Phone numbers | Counting with counters (개, 명, etc.) |
| Minutes (분), Seconds (초) | Objects, people, animals |
| Months, Floors | Numbers 1–99 in casual context |
| Numbers 100+ |