Definition:
Korean numbers operate as a dual system: native Korean numbers (고유어 수사 goyueo susa, pure Korean numerals) and Sino-Korean numbers (한자어 수사 hanjaeao susa, Chinese-origin numerals). The two sets are not interchangeable — their distribution across counting contexts follows conventional rules that must be explicitly learned, as there is no single rule that determines which system to use. Both systems are in active everyday use and native Korean speakers switch fluently between them depending on context.
The Two Number Series
Native Korean Numbers (1–20 core)
| Number | Native Korean | Romanization |
|---|---|---|
| 1 | 하나 (한) | hana (han before counter) |
| 2 | 둘 (두) | dul (du before counter) |
| 3 | 셋 (세) | set (se before counter) |
| 4 | 넷 (네) | net (ne before counter) |
| 5 | 다섯 | dasut |
| 6 | 여섯 | yeosut |
| 7 | 일곱 | ilgop |
| 8 | 여덟 | yeodeol |
| 9 | 아홉 | ahop |
| 10 | 열 | yeol |
| 20 | 스물 (스무) | seumul (seumu before counter) |
| 30 | 서른 | seoreun |
| 40 | 마흔 | maheun |
| 50 | 쉰 | swin |
| 100 | (not used above 99) | — |
Native Korean numbers only go up to 99 in regular use; above 99, Sino-Korean is used for native contexts too.
Sino-Korean Numbers
| Number | Sino-Korean | Romanization |
|---|---|---|
| 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 |
| 100,000,000 | 억 | eok |
Sino-Korean uses a base-10,000 system (not base-1,000 as in English): 10,000 is man (만), 100,000,000 is eok (억).
Distribution: Which System to Use
| Context | System | Example |
|---|---|---|
| Counting objects with most counters | Native Korean | 사과 세 개 (3 apples) |
| People (myeong/bun counters) | Native Korean | 세 명 (3 people) |
| Age (informal) | Native Korean | 스물다섯 살 (25 years old) |
| Clock hours | Native Korean | 세 시 (3 o’clock) |
| Clock minutes | Sino-Korean | 삼십 분 (30 minutes) |
| Dates (day of month) | Sino-Korean | 삼 일 (3rd day) |
| Months | Sino-Korean | 삼 월 (March) |
| Money | Sino-Korean | 삼천 원 (3,000 won) |
| Phone numbers | Sino-Korean | 공일공… (010…) |
| Floors of a building | Sino-Korean | 삼 층 (3rd floor) |
| Years | Sino-Korean | 이천이십오 년 (2025) |
| Bus/train numbers | Sino-Korean | 버스 삼백 번 (bus 300) |
A useful rough rule: native Korean for people, objects, and time (hours); Sino-Korean for dates, money, minutes, floors, and large quantities.
Time Telling: A Mixed System
Clock time in Korean mixes both systems:
- Hours use native Korean: 한 시 (1 o’clock), 두 시 (2 o’clock)
- Minutes use Sino-Korean: 삼십 분 (30 minutes), 오 분 (5 minutes)
So “3:30” is: 세 시 삼십 분 (se si samsip bun) — native + Sino-Korean mixed
Age and Korean System
Korean age counting traditionally uses a separate system:
- Informal Korean age (한국 나이 hanguk nai): everyone gains a year on New Year’s Day; a baby born in December is “2” on January 1st
- International age (만 나이 man nai — Sino-Korean): standard Western age; officially mandated since 2023 for all legal and administrative contexts
Counters and Number Agreement
Korean counters must be matched to the correct number series. Most general counters (개, 명, 마리, 권) require the native Korean series, while date/time/money counters use Sino-Korean. See the Korean Counters entry for the full distribution.
History
The dual number system reflects the same historical layering as native Korean vs. Sino-Korean vocabulary more broadly. The native number series is of indigenous Korean origin; the Sino-Korean numbers entered with Chinese cultural influence during the Three Kingdoms period and became dominant in formal, commercial, and official numerical contexts over the following centuries. Large quantity expressions (especially for finance and commerce) shifted primarily to Sino-Korean because these were domains dominated by Chinese-influenced education and administration.
The 2023 legal standardization of man nai (international age) was a significant language-policy change, ending centuries of dual age-counting in formal contexts.
Common Misconceptions
- “You can use either number system interchangeably.” The distribution is not free variation — using the wrong number system in a given context sounds clearly wrong (e.g., using Sino-Korean for telling clock hours)
- “Korean numbers go: il, i, sam, sa (always).” This is the Sino-Korean series only; many everyday counting tasks use the native Korean series
- “Native Korean numbers can handle large quantities.” The native system only goes reliably to 99; for hundreds and above, Sino-Korean is used even in contexts that normally prefer native numbers
Criticisms
- Pedagogical sequencing issues: many beginner Korean courses teach one number system first and introduce the other later, without clearly explaining the distribution rules, leading to persistent mixing errors
- Korean age complexity: until the 2023 reform, learners (and foreigners) needed to understand three distinct age-counting conventions (Korean age, international age, and a third civil age calculation), which created significant confusion
- Native number upper limit: the gap in the native system above 99 is an inconsistency that can cause learner errors when large quantities arise in otherwise native-number contexts
Social Media Sentiment
The dual Korean number system is one of the most-discussed structural quirks of Korean in learner communities. Teachers frequently post comparison tables and memory tricks. The time-telling mixed system (native hours + Sino minutes) generates particular discussion. The age reform in 2023 was a widely covered topic among Korean learners worldwide.
Last updated: 2025-05
Practical Application
Learning both Korean number systems in parallel — with clear context labels for when each is used — is more efficient than learning them sequentially. The clock time pattern (native hours / Sino minutes) is a practical early target since it comes up immediately in daily conversation.
Related Terms
See Also
Research
- Sohn, H.-M. (1999). The Korean Language. Cambridge University Press. — Provides systematic coverage of the Korean numeral system including both series, their morphological forms before counters, and the distributional rules governing context-appropriate number system selection.
- Yeon, J., & Brown, L. (2011). Korean: A Comprehensive Grammar. Routledge. — Reference grammar with complete tables for both number systems, counter pairing rules, and discussion of clock time, date, and age expressions with full examples.
- O’Grady, W. (1997). Syntactic Carpentry: An Emergentist Approach to Syntax. Erlbaum. — Includes discussion of Korean numeral classifier constructions and the interaction of number system selection with noun phrase structure, situating the dual system within theoretical syntax and acquisition.