The Korean language has two regularly used sets of numerals, a Sino-Korean system and a native Korean system.
The distinction between the two numeral systems is very important. Everything that can be counted will use one of the two systems, but seldom both. Sino-Korean words are sometimes used to mark ordinal usage: yeol beon (열 번) means "ten times" while sip beon (십(十) 번(番)) means "number ten."
When denoting the age of a person, one will usually use sal (살) for the native Korean numerals, and se (세) for Sino-Korean. For example, seu-mul da-seot sal (스물다섯 살) and i-sib-o se (이십오 세) both mean 'twenty-five-year-old'. See also East Asian age reckoning.
The Sino-Korean numerals are used to denote the minute of time. For example, sam-sib-o bun (삼십오 분) means "__:35" or "thirty-five minutes." The native Korean numerals are used for the hours in the 12-hour system and for the hours 0:00 to 12:00 in the 24-hour system. The hours 13:00 to 24:00 in the 24-hour system are only denoted using the Sino-Korean numerals. For example, se si (세 시) means '03:00' or '3:00 a.m./p.m.' and sip-chil si (십칠 시) means '17:00'.
For counting above 100, Sino-Korean words are used, sometimes in combination: 101 can be baek-hana or baeg-il.
Some of the native numbers take a different form in front of measure words:
| Number | Native Korean cardinals | Attributive forms of native Korean cardinals | ||||
|---|---|---|---|---|---|---|
| Hangul | McCune-Reischauer | Revised | Hangul | McCune-Reischauer | Revised | |
| 1 | 하나 | hana | hana | 한 | han | han |
| 2 | 둘 | tul | dul | 두 | tu | du |
| 3 | 셋 | set | set | 세 | se | se |
| 4 | 넷 | net | net | 네 | ne | ne |
| 20 | 스물 | sŭmul | seumul | 스무 | sŭmu | seumu |
The descriptive forms for 1, 2, 3, 4, and 20 are formed by "dropping the last letter" from the original native cardinal, so to speak. Examples:
Something similar also occur in some Sino-Korean cardinals:
The cardinals for three and four have alternatives forms in front of some measure words:
| Number | Sino-Korean cardinals | Native Korean cardinals | |||||
|---|---|---|---|---|---|---|---|
| Hanja | Hangul | Latin | Hangul | Latin | |||
| 0 | 零/〇 | 영 (N: 령), 공 | yeong (N: ryeong), gong | - | - | ||
| 1 | 一 | 일 | il | 하나 | hana | ||
| 2 | 二 | 이 | i | 둘 | dul | ||
| 3 | 三 | 삼 | sam | 셋 | saet | ||
| 4 | 四 | 사 | sa | 넷 | naet | ||
| 5 | 五 | 오 | o | 다섯 | daseot | ||
| 6 | 六 | 육 (N: 륙) | yuk (N: ryuk) | 여섯 | yeoseot | ||
| 7 | 七 | 칠 | chil | 일곱 | ilgop | ||
| 8 | 八 | 팔 | pal | 여덟 | yeodeol | ||
| 9 | 九 | 구 | gu | 아홉 | ahop | ||
| 10 | 十 | 십 | sip | 열 | yeol | ||
| 11 | 十一 | 십일 | sibil | 열 하나 | yeolhana | ||
| 12 | 十二 | 십이 | sibi | 열 둘 | yeoldul | ||
| 13 | 十三 | 십삼 | sipsam | 열 셋 | yeolset | ||
| 14 | 十四 | 십사 | sipsa | 열 넷 | yeollet | ||
| 15 | 十五 | 십오 | sibo | 열 다섯 | yeoldaseot | ||
| 16 | 十六 | 십육 (N: 십륙) | simnyuk (N: simryuk) | 열 여섯 | yeollyeoseot | ||
| 17 | 十七 | 십칠 | sipchil | 열 일곱 | yeorilgop | ||
| 18 | 十八 | 십팔 | sip-pal | 열 여덟 | yeollyeodeol | ||
| 19 | 十九 | 십구 | sipgu | 열 아홉 | yeorahop | ||
| 20 | 二十 | 이십 | isip | 스물 | seumul | ||
| 30 | 三十 | 삼십 | samsip | 서른 | seoreun | ||
| 40 | 四十 | 사십 | sasip | 마흔 | maheun | ||
| 50 | 五十 | 오십 | osip | 쉰 | swin | ||
| 60 | 六十 | 육십 (N: 륙십) | yuksip (N: ryuksip'') | 예순 | yesun | ||
| 70 | 七十 | 칠십 | chilsip | 일흔 | ilheun | ||
| 80 | 八十 | 팔십 | palsip | 여든 | yeodeun | ||
| 90 | 九十 | 구십 | gusip | 아흔 | aheun | ||
| 100 | 百 | 백 | baek | 온 | on | ||
| 1,000 | 千 | 천 | cheon | 즈믄 | jeumeun | ||
| 104 | 萬 | 만 | man | 드먼 | deumeon | ||
| 108 | 億 | 억 | eok | 잘 | jal | ||
| 1012 | 兆 | 조 | jo | - | - | ||
| 1016 | 京 | 경 | gyeong | 골 | gol | ||
| 1020 | 垓 | 해 | hae | - | - | ||
| 1024 | 秭 | 자 | ja | - | - | ||
| 1028 | 穰 | 양 | yang | - | - | ||
| 1032 | 溝 | 구 | gu | - | - | ||
| 1036 | 澗 | 간 | gan | - | - | ||
| 1040 | 正 | 정 | jeong | - | - | ||
| 1044 | 載 | 재 | jae | - | - | ||
| 1048 | 極 | 극 | geuk | - | - | ||
| 1052 or 1056 | 恒河沙 | 항하사 | hanghasa | - | - | ||
| 1056 or 1064 | 阿僧祇 | 아승기 | aseunggi | - | - | ||
| 1060 or 1072 | 那由他 | 나유타 | nayuta | - | - | ||
| 1064 or 1080 | 不可思議 | 불가사의 | bulgasaui | - | - | ||
| 1068 or 1088 | 無量大數 | 무량대수 | muryangdaesu | - | - | ||
Several numerals have long vowels, namely 둘 (two), 셋 (three) and 넷 (four), but these become short when combined with other numerals / nouns (such as in twelve, thirteen, fourteen and so on).
The usual liaison and consonant-tensing rules apply, so for example, 예순 여섯 (sixty-six) is pronounced like [예순녀섣] (yesunnyeoseot) and 칠십 chilsip (seventy) is pronounced like [칠씹] chilssip.
| one | 일 | 一 | 壹 |
| two | 이 | 二 | 貳 |
| three | 삼 | 三 | 參 |
| seven | 칠 | 七 | 柒 |
| ten | 십 | 十 | 拾 |
| hundred | 백 | 百 | 佰 |
| thousand | 천 | 千 | 仟 |