Most languages give you one set of numbers. Korean gives you two — and that single fact is why so many learners stall in week three. The good news: the two systems are not random, they do not overlap much, and once you know which one goes where, the rest is memorization you can finish in a weekend.
This guide covers both systems, the counter words that go with them, and the specific situations — time, money, age, dates, phone numbers — where Korean speakers switch between them without thinking.
Why Korean Has Two Number Systems
Korean borrowed heavily from Chinese over many centuries, and numbers came along with the vocabulary. Rather than replacing the original Korean numbers, the borrowed set settled alongside them and took over specific jobs. The result:
- Sino-Korean numbers (한자어 수사) — borrowed from Chinese. Used for anything that behaves like a measurement or a label: money, dates, minutes, addresses, phone numbers, floors, math.
- Native Korean numbers (고유어 수사) — the original Korean set. Used for counting physical things and people, telling the hour, and stating age.
English does something similar without noticing. We say “two o’clock” but “twenty-fourteen” for a year, and we say “second” instead of “two-th.” Korean just draws the line more sharply.
Sino-Korean Numbers (1–10 and Beyond)
Start here. Sino-Korean is the easier system: it is fully regular, it never runs out, and it covers more daily situations than the native set.
| Number | Hangul | 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 |
Building larger numbers is pure arithmetic. Say the multiplier, then the unit:
- 20 = 이십 (two-ten), 30 = 삼십, 90 = 구십
- 37 = 삼십칠 (three-ten-seven)
- 100 = 백, 500 = 오백, 1,000 = 천, 3,000 = 삼천
- 256 = 이백오십육
Two notes that trip people up. First, you do not say 일십 for 10 or 일백 for 100 — the “one” is dropped. Second, and more importantly, Korean groups large numbers by ten thousand (만), not by thousand. So 10,000 is 만, 100,000 is 십만 (ten ten-thousands), and 1,000,000 is 백만. A million won is 백만 원. Expect this to feel wrong for a few weeks; it becomes automatic with practice on real prices.
Also worth knowing: 0 is 영 in math and sports scores, but 공 when reading phone numbers.
Native Korean Numbers (1–99)
The native system is less regular and stops at 99, after which speakers borrow from Sino-Korean anyway.
| Number | Hangul | Romanization | Form before a counter |
|---|---|---|---|
| 1 | 하나 | hana | 한 |
| 2 | 둘 | dul | 두 |
| 3 | 셋 | set | 세 |
| 4 | 넷 | net | 네 |
| 5 | 다섯 | daseot | 다섯 |
| 6 | 여섯 | yeoseot | 여섯 |
| 7 | 일곱 | ilgop | 일곱 |
| 8 | 여덟 | yeodeol | 여덟 |
| 9 | 아홉 | ahop | 아홉 |
| 10 | 열 | yeol | 열 |
| 20 | 스물 | seumul | 스무 |
| 30 | 서른 | seoreun | 서른 |
| 40 | 마흔 | maheun | 마흔 |
| 50 | 쉰 | swin | 쉰 |
| 60 | 예순 | yesun | 예순 |
| 70 | 일흔 | ilheun | 일흔 |
| 80 | 여든 | yeodeun | 여든 |
| 90 | 아흔 | aheun | 아흔 |
Combine them the same way: 11 = 열하나, 25 = 스물다섯, 48 = 마흔여덟.
Notice that fourth column. This is the detail beginners skip and intermediate learners regret skipping. When a native number sits directly in front of a counter word, five of them shorten: 하나→한, 둘→두, 셋→세, 넷→네, 스물→스무. You count “하나, 둘, 셋” out loud, but you say 한 개 (one item), not 하나 개. Same for 스물다섯 살 — the 스물 keeps its full form here because it is followed by 다섯, not by the counter.
Counters: The Piece Nobody Warns You About
Korean cannot simply say “three books.” It needs a classifier between the number and the noun, the way English says “three sheets of paper” or “two cups of coffee.” The usual word order is noun + number + counter.
| Counter | Used for | Example |
|---|---|---|
| 개 | general objects | 사과 세 개 — three apples |
| 명 / 사람 | people (casual) | 학생 두 명 — two students |
| 분 | people (polite) | 손님 네 분 — four guests |
| 마리 | animals | 고양이 한 마리 — one cat |
| 권 | books | 책 다섯 권 — five books |
| 잔 | cups/glasses | 커피 두 잔 — two coffees |
| 병 | bottles | 맥주 세 병 — three beers |
| 장 | flat sheets, tickets | 표 두 장 — two tickets |
| 번 | times, occurrences | 세 번 — three times |
| 살 | years of age | 스무 살 — twenty years old |
All of these take native numbers. If you only memorize one, make it 개 — it works as a fallback for most inanimate objects, and a Korean listener will understand you even when a more specific counter exists.
When to Use Which: The Practical Split
| Situation | System | Example |
|---|---|---|
| Money | Sino | 오천 원 — 5,000 won |
| Minutes | Sino | 삼십 분 — 30 minutes |
| Hours (o’clock) | Native | 세 시 — 3 o’clock |
| Dates (year/month/day) | Sino | 오월 십일 일 — May 11th |
| Phone numbers | Sino | 공일공… — 010… |
| Counting objects/people | Native | 사람 네 명 — four people |
| Age (everyday) | Native | 서른 살 — 30 years old |
| Floors, room numbers | Sino | 삼 층 — 3rd floor |
| Measurements (km, kg) | Sino | 오 킬로 — 5 kilos |
The single most useful example is telling time, because it uses both systems in one breath. 3:20 is 세 시 이십 분 — native for the hour, Sino for the minutes. Say that phrase twenty times and the whole split will click.
Two Irregular Months
Months are Sino-Korean plus 월, but June and October drop a sound: June is 유월 (not 육월) and October is 시월 (not 십월). Every other month is regular — 일월, 이월, 삼월, and so on.
Common Mistakes to Avoid
- Using the full form before a counter. 네 개, not 넷 개. This is the single most common beginner error.
- Counting money with native numbers. Prices are always Sino-Korean: 만 오천 원, never 열다섯천 원.
- Translating “one million” as 천천. Regroup by 만: 1,000,000 = 백만.
- Forgetting sound changes. 십육 (16) is pronounced closer to simnyuk, and 육 often softens after certain consonants. Listen more than you read.
- Using native numbers past 99. They stop there. Above 100, everything is Sino-Korean.
A Seven-Day Practice Plan
- Days 1–2: Sino-Korean 1–10, then build to 999 out loud.
- Day 3: Prices. Read real Korean menus and say each price aloud.
- Days 4–5: Native 1–20 plus the five shortened counter forms.
- Day 6: Counters 개, 명, 잔, 번 with real objects around your room.
- Day 7: Time. Say every hour on the hour in Korean for one full day.
Frequently Asked Questions
Which Korean number system should I learn first?
Learn Sino-Korean first. It is perfectly regular, has no upper limit, and covers money, dates, and phone numbers — the situations you will hit first as a traveler or beginner. Add the native set once Sino-Korean 1–100 feels automatic.
Do native Korean numbers really stop at 99?
Yes, in practical modern use. Historical native words for 100 and above (such as 온 and 즈믄) exist but are archaic and appear only in poetry or older literature. From 100 onward, Korean speakers use Sino-Korean exclusively.
Why does telling time use both systems at once?
It is a historical accident rather than a rule with logic behind it: the hour retained the native counting word 시, while 분 (minute) came in as a Sino-Korean measurement term. Treat 세 시 이십 분 as a fixed pattern and it stops feeling strange.
Has anything changed about Korean age counting?
Yes. In June 2023 South Korea standardized official documents on international age (만 나이). In everyday conversation, though, people still state age with native numbers plus 살 — 스물다섯 살. The counting method changed; the number system did not.
Numbers are one of the few areas of Korean where a single hour with a tutor can save you weeks of confusion — mostly because you need someone to catch the counter-form slips your textbook can’t hear. Book a session with a Cognitio Korean tutor and practice both systems out loud, on real prices, real times, and real conversations.