Korean Has Two Number Systems. Here Is When to Use Each

Most languages have one set of numbers. Korean has two, they are unrelated, and fluent speakers switch between them several times in a single sentence without noticing. This is usually the first thing that makes a new learner feel the language is playing a trick on them.

It is not arbitrary. Each system owns a specific set of jobs, and once you know the division the choice becomes automatic.

The two sets, side by side

#Native KoreanRomanisedSino-KoreanRomanised
1하나hanail
2duli
3setsam
4netsa
5다섯daseoto
6여섯yeoseotyuk
7일곱ilgopchil
8여덟yeodeolpal
9아홉ahopgu
10yeolsip

Two useful facts about the tens. Native Korean has its own words — 스물 seumul (20), 서른 seoreun (30), 마흔 maheun (40), 쉰 swin (50) — and then stops at ninety-nine. There is no native word for a hundred. Sino-Korean simply stacks: 이십 isip is twenty, 삼십 samsip thirty, 백 baek a hundred, 천 cheon a thousand, 만 man ten thousand.

Which system goes where

Use native Korean forUse Sino-Korean for
Counting objects (사과 세 개 — three apples)Money (오천 원 — 5,000 won)
People (네 명 — four people)Dates and months (삼월 — March)
Age (스무 살 — twenty years old)Minutes and seconds (십 분 — ten minutes)
Hours on the clock (두 시 — two o'clock)Phone numbers
General counting up to 99Floors, addresses, measurements
Anything above 99

The shape-shifting four

Here is the detail that catches people who learned the list correctly. When a native number sits directly in front of a counter, four of them change form:

AloneBefore a counterExample
하나 hana한 han한 개 — one item
둘 dul두 du두 명 — two people
셋 set세 se세 시 — three o'clock
넷 net네 ne네 잔 — four cups
스물 seumul스무 seumu스무 살 — twenty years old

So you count "하나, 둘, 셋" out loud, but you order "커피 세 잔" — three coffees, not 셋 잔. The final consonant drops. From five upward nothing changes: 다섯 개, 여섯 명, 일곱 시 are all regular.

The clock uses both at once

This is the single most useful thing on this page. Telling the time in Korean takes a native number for the hour and a Sino-Korean number for the minutes:

TimeKoreanRomanised
1:00한 시han si
2:15두 시 십오 분du si sibo bun
3:30세 시 삼십 분se si samsip bun
7:45일곱 시 사십오 분ilgop si sasibo bun
10:05열 시 오 분yeol si o bun

Say it out loud once and it sticks. "Se si samsip bun" — the switch happens right at the word 시. Hours are things you count, so they take the counting system; minutes are measurements, so they take the Sino system. Every Korean clock time in the language follows this split.

Counters, briefly

Like Japanese and Chinese, Korean puts a counter between the number and the noun. The common ones:

CounterUsed forExample
generic objects사과 두 개 — two apples
people (plain)학생 세 명 — three students
people (polite)손님 네 분 — four guests
마리animals고양이 한 마리 — one cat
books책 다섯 권 — five books
cups and glasses커피 두 잔 — two coffees
years of age스무 살 — twenty years old

Note that 분 appears twice in this article with two different jobs — minutes, and a polite counter for people. Context separates them completely, and it is a good reminder that romanisation alone is not enough to read Korean reliably.

What to do first

Learn Sino-Korean one to ten and the units 백, 천, 만 before a trip, because prices, dates and addresses will not wait. Learn native one to ten alongside it, plus the five shape-shifting forms, and you will handle ordering, ages and the clock. That is a couple of evenings of work and it covers the overwhelming majority of numbers you will hear.

Check Korean readings offline

The free English-Korean Dictionary gives you Hangul with romanisation, so you can confirm whether a context wants 세 or 삼. No connection needed.

Open the dictionary app

Frequently asked questions

Why does Korean have two sets of numbers?

One set is native Korean and the other was borrowed from Chinese over centuries of contact, in much the same way English borrowed Latin and Greek number words alongside its Germanic ones. English kept its borrowings mostly for technical vocabulary — bicycle, decade, century — while Korean uses both systems in everyday speech, each in its own set of contexts.

Which Korean number system should a beginner learn first?

Learn Sino-Korean first if your priority is surviving transactions, because money, dates, phone numbers and addresses all use it and those are what you need on day one. Learn native Korean numbers one to ten early regardless, since they cover ages, hours and counting objects, and they stop at ninety-nine so there is far less to memorise.

How do you tell the time in Korean?

You use both systems in the same breath. The hour takes native numbers with the counter 시, and the minutes take Sino-Korean with 분. So 3:30 is 세 시 삼십 분 — se si sam sip bun. Mixing this up is one of the most common beginner errors and one of the easiest to fix once you have heard the pattern a few times.