Korean Numbers: Native vs Sino-Korean Counting Systems

Why Korean Has Two Number Systems

One of the first surprises for Korean learners is discovering that the language has not one but two complete number systems. The native Korean system (고유어 수 goyueo su) is the older of the two, rooted in the Korean language long before Chinese cultural influence reached the peninsula. The Sino-Korean system (한자어 수 hanjaeo su) arrived through centuries of scholarly exchange with China and became deeply embedded in formal, mathematical, and administrative contexts.

Today, both systems are used daily by every Korean speaker. You cannot get by with just one. When you tell a friend you are meeting at 3:30, you use native Korean for the hour (세 시 se si) and Sino-Korean for the minutes (삼십 분 samsip bun). When you buy something at a convenience store, the price is always in Sino-Korean (이천 원 icheon won, 2,000 won). When you tell someone your age, you use native Korean (스물다섯 살 seumuldaseot sal, 25 years old). Each system has its own domain, and mixing them up marks you as a beginner.

If you are preparing for the TOPIK exam, numbers appear at every level. The listening section tests your ability to hear prices, times, dates, and quantities. The reading section expects you to understand numbers in context. Getting comfortable with both systems early in your studies will pay dividends throughout your Korean learning journey.

Native Korean Numbers: 하나 Through 아흔아홉

The native Korean number system covers numbers from 1 to 99. Beyond 99, Korean switches exclusively to the Sino-Korean system. Let's start with the foundation: numbers 1 through 10.

Numbers 1-10

Notice that five numbers change their form when placed before a counter word: 하나 (hana) → 한 (han), 둘 (dul) → 두 (du), 셋 (set) → 세 (se), 넷 (net) → 네 (ne), and 스물 (seumul) → 스무 (seumu). This is one of the most important rules in Korean counting. You will almost never use the full form of these numbers when actually counting things. For example, "one person" is 한 명 (han myeong), not 하나 명. "Two animals" is 두 마리 (du mari), not 둘 마리.

Tens: 20 Through 90

The native Korean system has unique words for each multiple of ten, all the way up to 90. These are not combinations of smaller numbers — each is its own distinct word that must be memorized.

To form numbers between the tens, simply combine the ten with the unit. For example, 23 is 스물셋 (seumulset), 45 is 마흔다섯 (maheundaseot), and 71 is 일흔하나 (ilheunhana). Before a counter, 스물 changes to 스무: 스무 개 (seumu gae, twenty items), but 서른 through 아흔 do not change form. In practice, native Korean numbers above 50 or 60 are becoming less common in everyday speech, with many younger Koreans preferring Sino-Korean numbers for larger quantities.

If you are just starting to learn Hangul, focus on memorizing numbers 1 through 10 and the tens up to at least 50. These cover the vast majority of counting situations you will encounter in daily life and on the TOPIK Level 1 and Level 2 exams.

Sino-Korean Numbers: 일 Through 만 and Beyond

The Sino-Korean number system is based on Chinese characters (Hanja) and their Korean pronunciation. Unlike the native system, Sino-Korean numbers have no upper limit — they can express any quantity from zero to infinity. This system is used for dates, money, phone numbers, minutes, math, and formal contexts.

Basic Digits: 1-10

Larger Units

Building Sino-Korean numbers is systematic. You combine the digit with the place value: 11 is 십일 (sibil, ten-one), 25 is 이십오 (isibo, two-ten-five), 139 is 백삼십구 (baeksamsipgu, hundred-three-ten-nine), and 4,782 is 사천칠백팔십이 (sacheonchilbaekpalsib-i). The system is entirely regular with no exceptions for the basic building blocks.

Note that when the digit is 1, you often drop the 일 (il) before 십 (sip), 백 (baek), and 천 (cheon). For example, 100 is simply 백 (baek), not 일백 (ilbaek), and 1,000 is 천 (cheon), not 일천 (ilcheon). However, before 만 (man, 10,000), you do say 일만 (ilman) for 10,000 to distinguish it from other multiples.

When to Use Which System: The Complete Rule

This is the question every learner asks first, and fortunately the rules are clear. Here is the definitive breakdown of which number system to use in every common situation.

Use Native Korean Numbers For:

• Hours when telling time: 한 시 (han si) — 1 o'clock, 세 시 (se si) — 3 o'clock, 열두 시 (yeoldu si) — 12 o'clock
• Counting with most counters: 세 개 (se gae) — 3 items, 두 명 (du myeong) — 2 people, 다섯 마리 (daseot mari) — 5 animals
• Age (with 살 sal): 스물한 살 (seumulhan sal) — 21 years old, 서른두 살 (seoreundu sal) — 32 years old
• Counting objects in general: 사과 네 개 (sagwa ne gae) — 4 apples, 책 두 권 (chaek du gwon) — 2 books

Use Sino-Korean Numbers For:

• Dates: 삼월 십이일 (samwol sibiil) — March 12th
• Months: 일월 (irwol) — January, 십이월 (sibiwol) — December
• Years: 이천이십육 년 (icheonisimnyuk nyeon) — 2026
• Money: 삼천 원 (samcheon won) — 3,000 won
• Phone numbers: 공일공 (gongilgong) — 010
• Minutes and seconds: 삼십 분 (samsip bun) — 30 minutes, 십오 초 (sibo cho) — 15 seconds
• Floor numbers: 삼 층 (sam cheung) — 3rd floor
• Addresses and bus routes: 이백삼십 번 (ibaeksamsip beon) — number 230
• Mathematics: 이 더하기 삼 은 오 (i deohagi sam eun o) — 2 + 3 = 5

A helpful mnemonic: if the thing you are counting is abstract, official, or numerical (dates, money, measurements, phone digits), use Sino-Korean. If you are physically counting concrete objects or stating your age, use native Korean. The major exception to memorize is telling time, which mixes both systems.

Understanding Korean counters is closely tied to mastering numbers, because the counter determines which number system you use. Most counters take native Korean numbers, but a few important ones — including 분 (bun, minutes), 원 (won, money), 층 (cheung, floors), 번 (beon, number/times), and 호 (ho, room or issue number) — require Sino-Korean numbers.

Number Changes Before Counters

When native Korean numbers are placed directly before a counter word, five of them undergo a sound change. This is not optional — using the unmodified form before a counter sounds ungrammatical to native speakers. Here are the five changes you must memorize:

The remaining native Korean numbers (다섯 daseot, 여섯 yeoseot, 일곱 ilgop, 여덟 yeodeol, 아홉 ahop, 열 yeol, and the tens 서른 seoreun through 아흔 aheun) do not change form before counters. They are used exactly as-is: 다섯 명 (daseot myeong, five people), 열 개 (yeol gae, ten items), 서른 살 (seoreun sal, thirty years old).

For compound numbers like 21 or 24, only the ones digit changes: 스물한 개 (seumulhan gae, 21 items — 스물 changes to its base but 하나 becomes 한), 서른네 명 (seoreunne myeong, 34 people — 넷 becomes 네). Understanding this pattern is crucial for natural-sounding Korean and is frequently tested on TOPIK Level 1 and Level 2.

Telling Time: Where Both Systems Meet

Telling time in Korean is the perfect example of why you need both number systems. The hour uses native Korean numbers with 시 (si, o'clock), while the minutes use Sino-Korean numbers with 분 (bun, minutes). This mixing of systems feels odd at first but becomes natural with practice.

To specify AM or PM, Korean uses 오전 (ojeon) for AM and 오후 (ohu) for PM, placed before the time. For example, 오전 아홉 시 (ojeon ahop si) means 9:00 AM and 오후 세 시 삼십 분 (ohu se si samsip bun) means 3:30 PM. You can also use 반 (ban, half) as a shortcut for 30 minutes: 세 시 반 (se si ban) means 3:30. The word 정오 (jeongo) means noon and 자정 (jajeong) means midnight.

Remember that native Korean numbers change before 시: 한 시 (han si, 1 o'clock), 두 시 (du si, 2 o'clock), 세 시 (se si, 3 o'clock), 네 시 (ne si, 4 o'clock). From 5 o'clock onward, no change occurs: 다섯 시 (daseot si), 여섯 시 (yeoseot si), and so on up to 열두 시 (yeoldu si, 12 o'clock).

Counting Money: The 원 (Won) System

Korean currency is the 원 (won), and all money amounts use Sino-Korean numbers exclusively. This is one of the simpler rules to remember: whenever you see 원, think Sino-Korean. Korea does not use coins smaller than 10 won in practice, and most everyday transactions involve amounts in the hundreds or thousands.

A common point of confusion for English speakers is the 만 (man, 10,000) unit. English groups numbers by thousands (1,000 → 10,000 → 100,000), but Korean groups by ten-thousands (만 → 십만 → 백만 → 천만 → 억). So where an English speaker thinks "one hundred thousand," a Korean speaker thinks 십만 (simman, "ten ten-thousands"). This shift in thinking takes practice. A million won is not "one million" — it is 백만 원 (baengman won, "one hundred ten-thousands").

In everyday Korean life, you will encounter prices at restaurants (보통 삼천 원에서 만 원 botong samcheon won-eseo man won — usually 3,000 to 10,000 won), convenience stores, and transportation. Knowing how to hear and say prices fluently is essential for the TOPIK listening section and for survival in Korea.

Dates: Years, Months, and Days

All date expressions in Korean use Sino-Korean numbers. The order follows the East Asian convention: year → month → day, from largest to smallest. This is the opposite of the American month/day/year format and different from the European day/month/year format.

Months of the Year

Korean months are simply the Sino-Korean number followed by 월 (wol, month). There are no separate month names to memorize — January is literally "one-month," February is "two-month," and so on.

Notice two pronunciation irregularities: June is 유월 (yuwol), not 육월 (yukwol), and October is 시월 (siwol), not 십월 (sipwol). These are the only two months with irregular pronunciations, and they appear frequently on TOPIK exams as trick questions.

Days of the Month

Days use the counter 일 (il, day) with Sino-Korean numbers: 일일 (iril, 1st), 이일 (iil, 2nd), 삼일 (samil, 3rd), and so on. Unlike Japanese, Korean does not have irregular day readings — the system is entirely regular. The 15th is simply 십오일 (siboil), and the 31st is 삼십일일 (samsibilil).

Putting it all together, a full date like March 12, 2026 is: 이천이십육 년 삼월 십이일 (icheonisimnyuk nyeon samwol sibiil). In daily conversation, the year is often omitted when the context is clear, and many Koreans simply say 삼월 십이일 (samwol sibiil) for "March 12th."

Phone Numbers

Korean phone numbers are read digit by digit using Sino-Korean numbers. The standard mobile format in South Korea is 010-XXXX-XXXX. Each digit is read individually, and the groups are separated by a slight pause. The number zero is pronounced 공 (gong), not 영 (yeong), when reading phone numbers.

For example, the phone number 010-3456-7890 would be read as: 공일공 (gongilgong) — 삼사오육 (samsaoyuk) — 칠팔구공 (chilpalgu-gong). Each digit gets its own Sino-Korean reading. Some speakers group the last four digits in pairs for easier reading: 칠팔 (chilpal) 구공 (gugong).

Landline numbers vary by region. Seoul numbers start with 02, while other cities have three-digit area codes like 031 (Gyeonggi Province) or 051 (Busan). The same digit-by-digit reading applies. Listening practice with phone numbers is common on TOPIK Level 1 and Level 2, so get comfortable hearing and producing individual Sino-Korean digits quickly.

Large Numbers: Thinking in 만 (10,000)

The biggest conceptual hurdle for English speakers learning Korean numbers is the grouping system. English groups by thousands: thousand, million (a thousand thousands), billion (a thousand millions). Korean groups by ten-thousands: 만 (man, 10,000), 억 (eok, 100,000,000 — a ten-thousand ten-thousands), 조 (jo, 1,000,000,000,000 — a ten-thousand 억).

Here is how large numbers break down in the Korean system:

The practical impact of this system shows up when reading Korean news, discussing salaries, or talking about population. South Korea's population of roughly 52 million is expressed as 오천이백만 명 (ocheonibaekmman myeong — 5,200 ten-thousands of people). A salary of 40 million won per year is 사천만 원 (sacheonman won — 4,000 ten-thousands of won). Training yourself to mentally segment numbers at the ten-thousands boundary rather than the thousands boundary is essential for fluency.

For TOPIK Level 3 and above, you will encounter large numbers in reading passages about economics, demographics, and current events. Building comfort with 만 and 억 now will serve you well as you advance through higher levels. Check out our TOPIK Level 1 vocabulary lists for foundational number practice.

Common Mistakes to Avoid

Even intermediate learners regularly make errors with Korean numbers. Here are the most common pitfalls and how to avoid them:

1. Using Sino-Korean Numbers With Native-Korean Counters

Saying 삼 개 (sam gae) instead of 세 개 (se gae) for "three items" is one of the most common mistakes. The counter 개 (gae) takes native Korean numbers, so you must use the native Korean system. Conversely, saying 세 분 (se bun) instead of 삼 분 (sam bun) for "three minutes" is wrong because 분 (bun) takes Sino-Korean numbers. There is no shortcut here — you must memorize which system each counter requires.

2. Forgetting to Shorten Numbers Before Counters

Saying 하나 시 (hana si) instead of 한 시 (han si) for "one o'clock" is a telltale beginner mistake. Always remember the five changes: 하나 → 한, 둘 → 두, 셋 → 세, 넷 → 네, 스물 → 스무. Using the full form before a counter marks your speech as unnatural.

3. Confusing 유월 and 시월

June and October have irregular pronunciations: 유월 (yuwol) instead of the expected 육월 (yukwol), and 시월 (siwol) instead of 십월 (sipwol). These come up repeatedly on the TOPIK and in daily life. Many textbooks highlight these irregularities, but learners still forget them under pressure.

4. Thinking in Thousands Instead of Ten-Thousands

English trains you to think 100,000 as "one hundred thousand." In Korean, you must reconceptualize it as 십만 (simman, "ten ten-thousands"). This mental shift takes deliberate practice. When you hear a Korean price or statistic, resist the urge to translate it through English groupings. Instead, practice thinking directly in multiples of 만.

5. Using 영 Instead of 공 in Phone Numbers

While both 영 (yeong) and 공 (gong) mean zero, phone numbers and codes always use 공 (gong). Saying 영일영 (yeongillyeong) for "010" instead of 공일공 (gongilgong) sounds unnatural. Reserve 영 for mathematical and scientific contexts like temperature (영하 이도 yeongha ido, minus 2 degrees) or sports scores.

Understanding Korean particles is also important when using numbers in sentences, as the particle attached to the counted noun changes based on its grammatical role (을/를 for objects, 이/가 for subjects, etc.).

Practical Practice: Real-Life Scenarios

The best way to internalize Korean numbers is to practice them in realistic contexts. Here are everyday scenarios that combine different number types:

At a Restaurant

"We are two people" → 두 명이에요 (du myeong-ieyo) — native Korean + counter
"Three bottles of water, please" → 물 세 병 주세요 (mul se byeong juseyo) — native Korean + counter
"The total is 25,000 won" → 이만 오천 원이에요 (iman ocheon won-ieyo) — Sino-Korean + money

Making an Appointment

"March 20th at 2:30 PM" → 삼월 이십일 오후 두 시 삼십 분 (samwol isibil ohu du si samsip bun) — date in Sino-Korean, hour in native Korean, minutes in Sino-Korean
"My phone number is 010-1234-5678" → 공일공 일이삼사 오육칠팔 (gongilgong ilissamsa oyukchilpal) — all Sino-Korean digits

Shopping

"I want four of these" → 이거 네 개 주세요 (igeo ne gae juseyo) — native Korean + counter
"How much is this?" → 이거 얼마예요? (igeo eolmayeyo?)
"It is 8,900 won" → 팔천구백 원이에요 (palcheongubaek won-ieyo) — Sino-Korean

Talking About Age

"I am 28 years old" → 스물여덟 살이에요 (seumulyeodeol sal-ieyo) — native Korean + 살 (sal, age counter)
"My younger sibling is 19" → 제 동생은 열아홉 살이에요 (je dongsengeun yeorahop sal-ieyo) — native Korean
Note that in formal or written Korean, age can also use Sino-Korean with 세 (se): 이십팔 세 (isippal se, 28 years). The native Korean form with 살 is more common in everyday conversation.

Using spaced repetition to drill these scenarios is one of the most effective ways to build fluency with Korean numbers. Rather than memorizing number charts in isolation, practice them embedded in real phrases and sentences that you would actually use.

Numbers on the TOPIK Exam

Korean numbers appear across every section and every level of the TOPIK exam. Here is what to expect at each stage:

TOPIK Level 1-2 (TOPIK I): The listening section includes questions about times, prices, phone numbers, and dates. You will hear dialogues where someone asks for a price or states a meeting time, and you must select the correct answer. The reading section tests recognition of numbers in context, such as reading a schedule, menu, or calendar. Expect native Korean numbers 1-20 and Sino-Korean numbers for dates, prices, and times.

TOPIK Level 3-4 (TOPIK II): Numbers appear in longer listening passages about plans, itineraries, and transactions. You may need to process multiple numbers in a single passage — for example, a conversation about booking a hotel for a specific date range at a certain price. Reading passages include statistics, schedules, and quantitative descriptions.

TOPIK Level 5-6 (TOPIK II, advanced sections): At the highest levels, number comprehension is assumed to be automatic. Large numbers appear in passages about economics, demographics, and scientific data. The writing section may require you to describe quantitative information from graphs or charts using appropriate number expressions.

For a structured approach to exam preparation, see our TOPIK Level 1 study guide, which includes specific strategies for number-related questions.

Quick Reference: Which System for What