Korean numbers

Type any number and get it both ways. Korean has two counting systems and they are not interchangeable — one for money and dates, one for counting things and telling your age.

Why there are two sets

One set came from Chinese and one is native Korean, and both survived. Korean did not pick a winner — it split the work. Anything that behaves like a figure on paper takes the Sino-Korean set: money, years, dates, minutes, phone numbers, floors, addresses. Anything you can point at and count takes the native set: three cups, two people, five hours, and your age.

The native set stops at 99

There is no native word for a hundred in everyday use. Counting past ninety-nine, Koreans switch to the Sino-Korean set and keep going. So you will never need more than the first hundred native numbers — and in practice the ones under thirty do most of the work.

The part everyone gets wrong

Native numbers change shape when a counter word follows them. 하나 is one, but one book is 한 권, not 하나 권. The five that change are the five you will use most:

• 하나 → 한

  한 개, 한 시, 한 살
• 둘 → 두

  두 개, 두 시, 두 살
• 셋 → 세 / 넷 → 네

  세 개, 네 시
• 스물 → 스무

  스무 살. This one catches people out because it is the only tens word that changes.

Telling the time uses both at once

Three fifteen is 세 시 십오 분. The hour is native, the minutes are Sino-Korean, and the two sit in the same breath. It feels wrong for about a week and then it stops feeling like anything.

Two systems and what each one is for

Korean has two sets of numbers, and both are used every day. The native Korean set comes from the old language, and the Sino-Korean set comes from Chinese. The rule of thumb is simple. The native set is for counting things, ages and hours. The Sino-Korean set is for money, dates, minutes, years and numbers that are read off a page.

The native set, one to ten

The native numbers from one to ten are 하나, 둘, 셋, 넷, 다섯, 여섯, 일곱, 여덟, 아홉, 열. They change shape before a counter word. The first four are the ones people get wrong most: 한 개 for one thing, 두 개 for two, 세 개 for three, 네 개 for four. Before a counter, 하나 becomes 한, 둘 becomes 두, 셋 becomes 세, and 넷 becomes 네.

The Sino-Korean set, one to ten

The Sino-Korean numbers are 일, 이, 삼, 사, 오, 육, 칠, 팔, 구, 십. They are used for money, years, dates, phone numbers and minutes. 2026 is read as 이천이십육, and 1,500 won is 천오백 원. They do not change shape in front of a counter word.

Where each set is used

• Hours

  Native. Three o’clock is 세 시. Twelve o’clock is 열두 시.
• Minutes

  Sino-Korean. Fifteen minutes is 십오 분. So three fifteen is 세 시 십오 분: a native hour and Sino-Korean minutes in one phrase.
• Age

  Native up to ninety-nine. Two years old is 두 살, and twenty is 스무 살.
• Things you can count

  Native. Two cups is 두 잔, five books is 다섯 권.
• Money and prices

  Sino-Korean. Five thousand won is 오천 원.
• Dates

  Sino-Korean for the month and the day. March 1 is 삼월 일일. Some date words are native, such as 열흘 for ten days.

Counting past a hundred

The native set stops at about ninety-nine in everyday use. From a hundred up, Koreans use the Sino-Korean set. So 100 is 백, 1,000 is 천, and 10,000 is 만. The big units repeat in a clear pattern: 10,000 is 만, 15,000 is 만 오천, and 100,000,000 is 1억. This is why a number like 15,000 is read one unit at a time, as ten-thousand-and-five-thousand.

Reading larger numbers aloud

Read a long number in groups of four digits, from the right. The first group is the units, the second is 만, the third is 억. So 12,345,678 is split into 1234 and 5678: 1234 is 일천이백삼십사, then 5678 is 오천육백칠십팔, and the first group gets 만 in front of it: 일천이백삼십사만 오천육백칠십팔. In digits, that is 1234만 5678, which is 12,345,678. Splitting a number this way is the quickest check on whether you have read it right.

Speakers rarely say every unit. A round number is read with the unit only: 3억 is 삼억, and 2,000만 is 이천만. The small numbers in a long figure can be read out in full, but the big unit words carry the size.

Common mistakes

A few mistakes come up again and again.

• Ten is 십, not 일십

  Eleven is 십일, and twelve is 십이.
• Twenty for age is 스무, not 이십

  스무 살 is the form people use. 이십 살 is not the usual way to say it.
• Three or four people

  서너 명 is correct for three or four. 세네 명 is wrong.
• Counter words get a space

  In writing, leave a space between the number and the counter: 열 개, 스무 살, 두 시. The number and the unit are separate words.

When it is unclear

Some numbers can be read two ways. A price of 20,000 won is read as 이만 원, using 만 as the unit. A phone number is usually read one digit at a time. If you are not sure which set to use, go by the thing you are counting. If it is a thing or a person, use the native set. If it is a price, a date, a time on the clock or a number on a page, use the Sino-Korean set.