Korean has two complete sets of numbers, and you have to learn both. There is no way around it — telling the time uses one for the hour and the other for the minutes, in the same sentence.
The good news is that the dividing line is clear once you see it.
The two sets
| Native Korean | Sino-Korean | |
|---|---|---|
| 1 | 하나 | 일 |
| 2 | 둘 | 이 |
| 3 | 셋 | 삼 |
| 4 | 넷 | 사 |
| 5 | 다섯 | 오 |
| 6 | 여섯 | 육 |
| 7 | 일곱 | 칠 |
| 8 | 여덟 | 팔 |
| 9 | 아홉 | 구 |
| 10 | 열 | 십 |
| 20 | 스물 | 이십 |
| 30 | 서른 | 삼십 |
Native Korean numbers stop being practical around 99. Beyond that, everyone uses Sino-Korean.
Native Korean: counting things
Use native numbers with counters — the words that classify what you are counting.
| Counter | For |
|---|---|
| 개 | general objects |
| 명 | people |
| 마리 | animals |
| 병 | bottles |
| 잔 | cups, glasses |
| 시간 | hours (duration) |
| 살 | years of age |
- 사과 세 개 — three apples
- 두 명 — two people
- 커피 한 잔 — one cup of coffee
- 스무 살 — twenty years old
The first four numbers change shape before a counter:
하나 → 한 · 둘 → 두 · 셋 → 세 · 넷 → 네
And 스물 → 스무.
So it is 한 개, not 하나 개. This is one of the most common beginner errors and one of the most noticeable.
Sino-Korean: everything measured
Use Sino-Korean numbers for anything on a scale or a system.
| Use | Example |
|---|---|
| Money | 삼천 원 (3,000 won) |
| Minutes | 삼십 분 |
| Dates | 오월 오일 (May 5) |
| Months | 육 개월 (six months) |
| Phone numbers | 공일공… |
| Floors | 삼 층 |
| Bus and subway lines | 이호선 |
Telling the time uses both
This is the sentence that forces you to know the split.
세 시 삼십 분 — 3:30
시 (hour) takes native numbers. 분 (minute) takes Sino-Korean. Every single time.
- 한 시 십 분 — 1:10
- 여덟 시 사십오 분 — 8:45
- 열두 시 — 12:00
If you say 삼 시, a Korean will understand you and also immediately know you are learning.
Age
Age uses native numbers with 살.
- 스무 살 — 20 years old
- 서른 살 — 30 years old
- 스물다섯 살 — 25 years old
In formal contexts you may hear the Sino-Korean form with 세: 이십오 세. Documents and news use it; conversation does not.
Large numbers group by 10,000
English groups numbers in thousands. Korean groups them in ten-thousands, and this is a genuine mental adjustment.
| Korean | Value |
|---|---|
| 만 | 10,000 |
| 십만 | 100,000 |
| 백만 | 1,000,000 |
| 천만 | 10,000,000 |
| 억 | 100,000,000 |
So 30,000 won is 삼만 원, not 삼십 천. And a Korean apartment priced at 5억 is 500 million won.
Prices are where this matters most. Getting comfortable with 만 as a unit — rather than converting from thousands each time — makes shopping much faster.
A shortcut that mostly works
If the thing you are counting has a counter word after it, use native numbers. If you are stating a measurement, price, or position in a system, use Sino-Korean.
That covers the great majority of cases, and the exceptions are few enough to learn individually.
Getting it into your ear
Numbers are hard to drill from a chart because they only stick in context — a price you paid, a time you agreed, an order you placed.
K-PATTO episodes are full of ordinary transactions where both systems show up naturally, with audio so you hear the difference between 세 시 and 삼 시 rather than reading about it. The first ten are free at K-PATTO.