Here’s a moment every Korean learner has lived through. You walk into a café in Seoul, confidently order, and then the cashier says the price. You freeze. You heard numbers — you’re sure of it — but nothing you learned last week seems to fit.

The reason isn’t your listening skills. It’s that Korean has two completely separate number systems, and they are not interchangeable. Use the wrong one and a native speaker will understand you, but you’ll sound like someone saying “I am the third years old.”

The good news: the rules for choosing between them are surprisingly consistent. In this guide you’ll learn both systems from 1 to 100 and beyond, the counter words that go with them, exactly which system to use for money, time, age, and dates, and the four mistakes that trip up almost every beginner. There’s a practice quiz at the end.

Why Korean Has Two Number Systems

Korean uses two sets of numbers because of history, not to make your life harder.

Native Korean numbers (고유어 수사, goyueo susa) are the original Korean words. They developed on the peninsula and are used for counting things you can see and touch.

Sino-Korean numbers (한자어 수사, hanjaeo susa) came from Chinese, absorbed into Korean over roughly two thousand years. They handle abstract and technical quantities: money, measurements, dates, phone numbers.

English actually does something similar, though we rarely notice. We say two but also second, duo, binary, and double — the same quantity, expressed through different historical layers of the language. Korean simply keeps its two layers more visibly separate.

Sino-Korean Numbers 1–10

Start here. Sino-Korean is the easier system because it’s fully regular — there are no irregular forms to memorize past ten.

Building 11 to 99

Sino-Korean numbers stack together exactly the way the digits look. There is no “eleven” or “twelve” to memorize separately.

Hundreds, Thousands, and the 만 Problem

This is where Korean genuinely differs from English, and it’s worth slowing down for.

To read a large number, split it from the right in groups of four:

250,000 → 25|0000 → 이십오만 (isibo-man)
1,500,000 → 150|0000 → 백오십만 (baek-osip-man)
32,000,000 → 3200|0000 → 삼천이백만 (samcheon-ibaek-man)

Native Korean Numbers 1–99

Native Korean numbers are less regular, and there are fewer of them — the system runs out at 99. Beyond that, everyone switches to Sino-Korean.

The tens each have their own word, which is the part that takes real practice:

Combining works the same way as Sino-Korean — tens word plus ones word, no connector: 열둘 (12), 스물셋 (23), 마흔일곱 (47), 아흔아홉 (99).

The Shortening Rule Nobody Warns You About

Here is the single most useful thing in this article, and it’s the reason your textbook numbers sound wrong in real conversation.

When a Native Korean number comes directly before a counter word, five of them change shape.

Every other number keeps its shape: 다섯 개, 열 명, 서른 살, 아흔아홉 개. And note that in compound numbers, only the final digit shortens — 21 items is 스물한 개, not 스무한 개.

Counter Words: The Piece That Makes Numbers Usable

Korean can’t simply say “three cats.” It needs a classifier between the number and the thing being counted, similar to how English says “three sheets of paper” or “two loaves of bread” — except Korean does this for everything.

The standard word order is: noun + number + counter.

커피 두 잔 (keopi du jan) — two coffees
고양이 세 마리 (goyangi se mari) — three cats
책 다섯 권 (chaek daseot gwon) — five books

Counters that take Native Korean numbers

Counters that take Sino-Korean numbers

Telling Time: Where Both Systems Meet

Korean clock time is the one place both systems appear inside a single phrase — and it catches nearly every learner off guard.

Hours use Native Korean. Minutes use Sino-Korean. Always. There are no exceptions.

For AM and PM, Korean puts the marker first: 오전 (ojeon) for AM, 오후 (ohu) for PM. So 2 PM is 오후 두 시 (ohu du si).

Money, Age, Dates, and Phone Numbers

Money — always Sino-Korean

Korean prices are spoken in 만 units, which takes adjusting to when everything costs thousands of won.

3,000원 → 삼천 원 (samcheon won)
15,000원 → 만 오천 원 (man ocheon won)
48,000원 → 사만 팔천 원 (saman palcheon won)
250,000원 → 이십오만 원 (isibo-man won)

Notice that 10,000 is just 만, not 일만, in everyday speech. You’ll see 일만 written on bank forms and cheques, but nobody says it out loud at a shop counter.

Age — Native Korean with 살

스물세 살 (seumulse sal) — 23 years old
서른 살 (seoreun sal) — 30 years old
마흔여섯 살 (maheunyeoseot sal) — 46 years old

There is also a formal Sino-Korean version using 세 (se) — 이십삼 세 — but you’ll only meet it in documents, news reports, and hospital forms. In conversation, use 살.

Dates — Sino-Korean, with two irregulars

Korean dates run largest to smallest: year, then month, then day.

2026년 3월 15일 → 이천이십육 년 삼월 십오 일

Two months change their pronunciation for ease of speech, and they are not optional:

Phone numbers — Sino-Korean, digit by digit

Korean phone numbers are read one digit at a time, using 공 for zero. The dash is read as 에 (e) or simply paused over.

010-1234-5678 → 공일공 일이삼사 오륙칠팔

Four Mistakes Almost Every Learner Makes

1. Using Native Korean for money

Saying 다섯 원 instead of 오 원 is the classic slip. Money is always Sino-Korean — no exceptions, no matter how small the amount.

2. Forgetting the counter word

커피 둘 주세요 sounds incomplete, like saying “give me two coffee” and stopping mid-sentence. You need 커피 두 잔 주세요. When you can’t remember the right counter, 개 is an acceptable fallback for most objects.

3. Skipping the shortened forms

하나 개, 둘 명, 셋 시 — all wrong, and all extremely common. Before a counter, it’s 한 개, 두 명, 세 시.

4. Counting large numbers in thousands

Trying to say 1,000,000 as “일천천” doesn’t work. Regroup in fours first: 100|0000 → 백만.

Quick Reference: Which System Do I Use?

If you’re heading to Korea and want to see these numbers in the wild, fares, line numbers, and exit numbers all use Sino-Korean — our guide to using the Korean subway system walks through the signs and phrases you’ll actually encounter.

Practice Quiz

Frequently Asked Questions

Which number system should I learn first?

Sino-Korean. It’s fully regular, it covers money and dates (which you’ll need on day one in Korea), and it extends infinitely. Learn Native Korean second, focusing on 1 through 20 plus the tens — that range covers the overwhelming majority of real-world counting.

Do I really need to memorize all the counter words?

No. Start with six: 개 (objects), 명 (people), 잔 (drinks), 마리 (animals), 살 (age), 시 (hour). These will carry you through most everyday conversations, and 개 works as a substitute in a pinch.

Why does Korean stop Native numbers at 99?

Native Korean historically did have words for larger amounts — 온 for 100, 즈믄 for 1,000 — but they fell out of use centuries ago as Sino-Korean took over the higher ranges. Today they survive only in poetry and old texts.

How long does it take to get comfortable with both systems?

Most learners can recite both sets within a week. Choosing the right one automatically, without pausing to think, typically takes one to two months of regular practice. Ordering food and reading prices out loud accelerates this more than flashcards do.

Do Koreans ever mix the systems by mistake?

Rarely, and when it happens it’s usually in fixed phrases where usage has drifted. One you’ll hear often: at a restaurant, portions are technically 이 인분 (Sino), but people frequently say 두 개 when pointing at a menu. Native speakers navigate by habit rather than rule — which is exactly what you’re building toward.

Putting It Into Practice

Numbers are one of the few areas in Korean where you get instant, unavoidable feedback: order a coffee, and you’ll know within seconds whether you got it right. That makes them ideal for early practice.

Try this for one week. Every time you look at a clock, say the time in Korean. Every time you see a price, convert it. Every time you count anything — stairs, emails, people in a queue — attach a counter. Ten seconds at a time, several times a day, will do more than an hour of drilling on Sunday.

Once numbers feel automatic, the natural next step is sentence-level Korean. Our guides to Korean particles and Korean honorifics cover the two systems that turn vocabulary into real sentences.

Written by Minhyung Cha, founder of Korean English Lab, with over 25 years of experience teaching Korean and English.

Numbers belong to stage three of five. Our step-by-step plan for learning Korean lays out the whole path, week by week.