Sino-Korean Numbers in Korean

In Brief

Sino-Korean numbers are 일, 이, 삼, 사, 오..., the number words of Chinese origin used in Korean. Use them for dates, money, minutes, phone numbers, measurements, mathematics, and most large numbers: 오월 십오일 means “May 15,” and 천 원 means “1,000 won.” Korean also has a native number system, so choosing the right set matters as much as learning the numbers themselves.

Overview

Korean has two everyday number systems. Sino-Korean numbers (한자어 수사) came into Korean through Chinese characters and now appear wherever numbers behave like labels, calculations, dates, prices, or formal quantities. You will hear them in shops, on public transport, in addresses, and whenever someone gives a phone number.

This is an A1 topic because the basic pattern is highly regular. Learn nine digits plus the place-value words 십 (10), 백 (100), 천 (1,000), and 만 (10,000), and you can build an enormous range of numbers. Unlike English, however, Korean groups large numbers around ten thousand, not only around thousand. That difference becomes important once you move beyond four digits.

For an English-speaking learner, the main adjustment is selection. English uses the same “three” in “three hours,” “three minutes,” and “three dollars.” Korean normally uses native Korean 세 for three hours but Sino-Korean 삼 for three minutes and amounts of money. The choice belongs to the expression as a whole; it is not simply a formal-versus-informal distinction.

How It Works

The basic numbers

Number	Korean	Romanization	Typical note
0	영 / 공	yeong / gong	영 is general; 공 is common in phone numbers and codes
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

Romanization is a Latin-letter pronunciation guide. Treat it as temporary support: Hangul shows Korean pronunciation more reliably than English spelling can.

Building numbers up to 9,999

The structure is digit + place value, read from largest place to smallest. There is no equivalent of English “and” inside a number.

Number	Structure	Korean
11	10 + 1	십일
20	2 × 10	이십
25	2 × 10 + 5	이십오
100	100	백
106	100 + 6	백육
340	3 × 100 + 4 × 10	삼백사십
1,000	1,000	천
2,024	2 × 1,000 + 2 × 10 + 4	이천이십사
9,999	9 × 1,000 + 9 × 100 + 9 × 10 + 9	구천구백구십구

Before 십, 백, and 천, an initial 일 is normally omitted: say 십, not 일십, for 10; 백, not 일백, for 100; and 천, not 일천, for 1,000. Zero places are simply skipped. That is why 106 is 백육, not a word-by-word reading that inserts zero.

Large-number units

Korean uses units based on groups of four digits. 만 is 10,000, 억 is 100,000,000, and 조 is 1,000,000,000,000.

Value	Unit	Example
10,000	만	만 원 — 10,000 won
100,000	십만	십만 원 — 100,000 won
1,000,000	백만	백만 원 — 1,000,000 won
10,000,000	천만	천만 원 — 10,000,000 won
100,000,000	억	일억 원 — 100,000,000 won
1,000,000,000	십억	십억 원 — 1,000,000,000 won
1,000,000,000,000	조	일조 원 — 1,000,000,000,000 won

For 만, Korean normally says 만, not 일만, when it stands alone. With 억 and 조, 일 is ordinarily included: 일억, 일조. To read a long number, separate it from the right into four-digit blocks: 123,456,789 becomes 1억 + 2,345만 + 6,789, or 일억 이천삼백사십오만 육천칠백팔십구.

English-speaking learners often mentally group 1,000,000 as “one million.” Korean instead sees it as 백만, literally “one hundred ten-thousands.” Learning to spot 만 as a unit is faster than repeatedly translating through “thousand” and “million.”

Numbers as quantities and numbers as digit strings

A quantity is built with place values: 25 is 이십오. A phone number, room number, PIN, or other identifier is often read one digit at a time: 25 may then be 이 오. The situation tells you which reading is intended.

Phone numbers are normally split into groups, with 에 or a pause where a hyphen appears. Zero is often 공 in this setting. For example, 010-2345-6789 can be read 공일공에 이삼사오에 육칠팔구. Actual delivery varies, but the essential beginner habit is to read each digit rather than turning a phone-number group into a quantity.

Dates, months, years, and time

Dates follow the order year + 년 + month + 월 + day + 일. All numerical parts use Sino-Korean numbers.

• 2026년 5월 15일 — 이천이십육 년 오월 십오일 — May 15, 2026
• 3월 — 삼월 — March
• 21일 — 이십일일 — the 21st day of the month

Two months have contracted standard pronunciations and spellings: June is 유월, not 육월, and October is 시월, not 십월. These are fixed month names.

Clock time mixes the two systems. Hours use native Korean numbers with 시, while minutes and seconds use Sino-Korean numbers with 분 and 초:

• 세 시 십오 분 — 3:15
• 한 시 오 분 삼십 초 — 1:05:30

This mixed pattern is normal. Do not try to make every part of the clock use the same system.

Money, measurements, and other common units

Amounts of money normally use Sino-Korean numbers: 오천 원 (5,000 won), 만 이천 원 (12,000 won). Sino-Korean numbers are also standard with many measurement and technical units, including 킬로미터 (kilometres), 미터 (metres), 킬로그램 (kilograms), 퍼센트 (percent), and temperature in 도 (degrees).

Many numbered labels and institutional expressions also use them: 삼 층 (third floor), 이 번 (number two), 일 학년 (first school year/grade), and 사 호실 (room number four). Spacing can depend on the unit and writing convention, but the number system remains Sino-Korean.

Examples in Context

Korean	English	Note
일, 이, 삼, 사, 오	1, 2, 3, 4, 5	Basic Sino-Korean digits
육, 칠, 팔, 구, 십	6, 7, 8, 9, 10	Basic digits through ten
오늘은 오월 십오일이에요.	Today is May 15.	Month and date use Sino-Korean numbers
제 생일은 유월 이십일이에요.	My birthday is June 20.	June is the irregular form 유월
이 책은 만 이천 원이에요.	This book is 12,000 won.	A price using 만
커피는 사천오백 원이에요.	The coffee is 4,500 won.	Zero places are omitted
지금 세 시 십 분이에요.	It is 3:10 now.	Native 세 for the hour; Sino-Korean 십 for minutes
수업은 구십 분 동안 계속돼요.	The class lasts for 90 minutes.	Minutes use Sino-Korean numbers
제 전화번호는 공일공에 이삼사오에 육칠팔구예요.	My phone number is 010-2345-6789.	Digits are read separately; 공 means zero
사무실은 삼 층에 있어요.	The office is on the third floor.	Floors normally use Sino-Korean numbers
서울까지 이십 킬로미터예요.	It is 20 kilometres to Seoul.	Measurement
할인율은 십오 퍼센트예요.	The discount is 15 percent.	Percentage
이천이십육 년에 한국에 가요.	I am going to Korea in 2026.	Years use Sino-Korean numbers
정답은 이 번이에요.	The correct answer is number two.	A numbered choice or label

Common Mistakes

Using native Korean numbers for prices

• Wrong: 천 원 expressed as 한 천 원
• Right: 천 원
• Why: Prices use Sino-Korean place values. The number 1 is normally omitted before 천, so 1,000 won is simply 천 원.

Reading every number as a quantity

• Wrong: reading the phone-number group 2345 as 이천삼백사십오
• Right: 이삼사오
• Why: A phone number is an identifier, not an amount. Read its digits individually.

Saying 육월 and 십월 for the month names

• Wrong: 육월, 십월
• Right: 유월 (June), 시월 (October)
• Why: These two month names use fixed contracted forms. Other months follow the regular number + 월 pattern.

Using Sino-Korean numbers for clock hours

• Wrong: 삼 시 십 분
• Right: 세 시 십 분
• Why: Hours use native Korean numbers, while minutes use Sino-Korean numbers. This is one of the most common mixed-system expressions.

Following English three-digit grouping when reading large numbers

• Wrong habit: trying to translate 1,000,000 directly as “one million” before forming the Korean number
• Right: 백만
• Why: Korean large units advance around 만 (10,000). Split long figures into four-digit groups from the right.

Inserting zero into a quantity

• Wrong: 백영육 for 106
• Right: 백육
• Why: Empty place values are silent in quantities. 영 or 공 is spoken when zero itself matters, especially in decimals, scores, codes, and digit strings.

Usage Notes

영 and 공 are not always interchangeable

Both can represent 0, but their typical settings differ. 영 is the general mathematical zero and appears in temperatures, scores, and decimal quantities. 공, literally associated with an empty value, is especially common while dictating phone numbers, account numbers, and codes. A phone number beginning 010 is therefore usually 공일공.

In sports scores, broadcast conventions, mathematics, and specialised contexts, the preferred reading may vary. At beginner level, 영 for a numerical zero; 공 for a digit in a code or phone number is a useful working rule.

Spacing and pronunciation

Written numbers and their units can appear with spacing that follows Korean dependent-noun and unit conventions: 천 원, 십 분, 삼 층. In real signs and price labels, Arabic numerals are extremely common: 1,000원, 15분, 3층. You still need the Sino-Korean reading when saying them aloud.

Hangul sounds also influence one another in connected speech. For example, 십육 (16) is pronounced more like 심뉵 than a careful letter-by-letter 십-육. Learn the transparent written structure first, then copy natural audio rather than forcing every syllable to remain separate.

Age can use either system in different settings

Everyday age commonly uses native Korean numbers with 살, as in 스물다섯 살 (25 years old). Sino-Korean numbers occur with 세, a more formal age counter found on forms, in announcements, and in official or medical contexts: 이십오 세. This is not free substitution; the counter and register change together.

Beyond the Basics / Advanced Use

You do not need to master all of the following at A1, but these patterns make the system a complete foundation for later study.

Decimals, fractions, and arithmetic

Decimals use 점 (“point”), and digits after the decimal point are normally read separately:

• 3.14 — 삼 점 일사
• 0.5 — 영 점 오

Fractions commonly use the pattern denominator + 분의 + numerator:

• 1/2 — 이분의 일
• 3/4 — 사분의 삼

This order is the reverse of how an English speaker first sees the written fraction: 사분의 삼 is literally “three out of four,” with four named first in the Korean construction.

Arithmetic uses Sino-Korean readings as well. Expressions such as 이 더하기 삼은 오 (“two plus three is five”) reinforce the same digit set.

Large exact figures and abbreviated speech

News reports, finance, property prices, and population statistics routinely combine 만, 억, and 조. Written forms may mix Arabic digits and Korean units, such as 3억 5천만 원 (350 million won). In fast speech, context does much of the work, so losing track of a single large-number unit can change the amount drastically.

Build from the units rather than from an English translation:

1. Mark four-digit blocks from the right.
2. Name each block below 10,000.
3. Add 만, 억, or 조 to the block.
4. Skip any block whose value is zero.

For example, 305,020,000 is 삼억 오백이만, because it consists of 3억 + 502만. The absence of a spoken unit for an empty place is normal.

Number readings inside vocabulary

Sino-Korean number roots occur in many established words and expressions: 일등 (first place), 삼각형 (triangle, literally a three-angled shape), and 사계절 (the four seasons). These are vocabulary items rather than freely built counting phrases. Recognising the number root can help memory, but meaning and pronunciation should be learned with the whole word.

The number 4, 사, sounds like the Sino-Korean word associated with death, 사. Because of that homophony (two words that sound alike), some buildings or institutions avoid a fourth-floor label or replace 4 with F. Practices vary, and ordinary counting with 사 remains completely normal.

Practice Tips

1. Build numbers in both directions. Write five figures such as 47, 308, 6,250, 70,000, and 2,000,000; read them in Korean, then cover the figures and reconstruct them from the Korean forms. Include 만 every day until four-digit grouping feels automatic.
2. Sort expressions by number system. Make two columns: native Korean and Sino-Korean. Put hours and everyday counting in one; dates, prices, minutes, phone numbers, and measurements in the other. Add mixed expressions such as 세 시 십 분 to both sides with a note.
3. Practise real strings, not only lists. Read prices from Korean shopping pages, dates from a calendar, and fictional phone numbers aloud. Say quantities with place values but codes digit by digit.

Related Concepts

• Prerequisite: Native Korean Numbers — compare the number set used for many counters, age, and clock hours.
• Next step: Time Expressions — combine native Korean hours with Sino-Korean minutes and use numbers in everyday schedules.