Korean numbers have two different pronunciations and usages:

1. Sino-Korean (originally from Chinese and using Hanja)
2. Pure Korean (always Hangul)

Sino-Korean numbers are used for:

1. Prices
2. Telephone numbers
3. Bus/subway numbers
4. Dates
5. Height & weight
6. Time in minutes & seconds

Sino-Korean numbers can be used basically as stand-alone numbers.

Pure Korean numbers are used primarily for:

1. Counting units

This includes:

1. Numerical counting (1st, 2nd, 3rd, etc)
2. Counting things (5 people)
3. Counting age (I’m 25)
4. Counting time in hours (2 o’clock; 2 hours)

Pure Korean numbers typically include a unit noun to indicate the appropriate measure.

Table

 Number 1 2 3 4 5 6 7 8 9 10 Pure Korean 하나 (한) 둘 (두) 셋 (세) 넷 (네) 다섯 여섯 일곱 여덟 아홉 열 Sino-Korean 일 이 삼 사 오 육 칠 팔 구 십 Hanja 一 二 三 四 五 六 七 八 九 十 11 20 30 40 50 60 70 80 90 100 Pure Korean 열하나 스물 (스무) 서른 마흔 쉰 예순 일흔 여든 아흔 백 Sino-Korean 십일 이십 삼십 사십 오십 육십 칠십 팔십 구십 백 Hanja 十一 二十 三十 四十 五十 六十 七十 八十 九十 百 0 1,000 10,000 100,000 1,000,000 Sino-Korean 영 (공) 천 만 십만 백만 Hanja 零 千 萬 十萬 百萬 10,000,000 100,000,000 1,000,000,000 Sino-Korean 천만 억 십억 Hanja 千萬 億 十億

Notes:

1. The base for counting large numbers is 10,000 (만). In English, it is 1,000. (This can make large numbers confusing.)
2. When a large number starts with 1, you don’t say the 1. Example: 1,110 = 천백십 not 일천백십.
3. 영 is the word for “zero” but always use 공 in a telephone number. (Also, sometimes use 하나 in place of 일 because it sounds so close to 칠.)
4. Anything with something in the tens place and a 6 is pronounced as 뉵 rather than 육. Example: 16 = 십뉵, 26 = 이십뉵, … 96 = 구십뉵, but 106 = 백육. (Spelling isn’t different, only pronunciation.)