Sino-Korean Numbers

Sino-Korean numbers work like LEGO bricks. You have ten basic blocks. You stack them to make bigger numbers. There are no weird irregular changes like 'eleven' or 'twelve' in English. In Korean, 11 is just 10 plus 1. It is very predictable. You don't have to memorize hundreds of unique words. You only need to learn the sounds for 0 through 10. After that, it is just simple addition and multiplication. Think of it like a grammar calculator. If you can count to ten, you can count to 999. It is a very efficient system. Even native speakers appreciate how fast it is to say. It feels modern and precise. You will hear these numbers everywhere from the subway to the news.

1. 1First, memorize the core ten: 일 (1), 이 (2), 삼 (3), 사 (4), 오 (5), 육 (6), 칠 (7), 팔 (8), 구 (9), 십 (10).
2. 2To make numbers 11-19, start with 10 (십) and add the single digit. For example, 11 is 십일 (10+1). 15 is 십오 (10+5).
3. 3To make multiples of 10 (20, 30, etc.), put the single digit before 10. For example, 20 is 이십 (2x10). 50 is 오십 (5x10).
4. 4To make complex numbers like 42, combine both rules. 40 is 사십 and 2 is 이. So 42 is 사십이.
5. 5For zero, use 영 for math or temperature. Use 공 for phone numbers. It is like saying 'zero' vs 'oh' in English.
6. 6For 100, use the word 백. For 1,000, use 천. For 10,000, use 만.

Use Sino-Korean numbers for anything involving 'data'. Money is the most common use. If you are buying a cool K-pop album, the price is in Sino-Korean. Dates are also strictly Sino-Korean. This includes the year, month, and day. When you tell someone your phone number, use this system. It is also used for minutes and seconds on the clock. If you are at a restaurant and looking at floor numbers, look for these. Bus numbers and room numbers also use this system. Think of it as the 'official' number system. If it's on a receipt or a digital screen, it's likely Sino-Korean. It is the language of business and organization.

Do not use Sino-Korean numbers for counting physical things. If you are counting apples or people, use the Native system. Age is a big one to avoid. Telling someone you are 이십 (20) years old sounds like a robot. Use the Native system for age instead. Hours on a clock are also tricky. While minutes use Sino-Korean, the hour uses Native Korean. This is the 'grammar traffic light' that trips everyone up. Don't use Sino-Korean for 'times' as in 'three times'. Basically, if you can physically touch the items or you are talking about hours/age, stay away. It takes practice, but you will get the hang of it.

Mixing up 일 (1) and 이 (2) is very common. They sound very similar in a noisy market. Many learners accidentally use Sino-Korean for their age. This makes you sound like a historical document. Another mistake is saying 일십 for 10. Just say 십. You don't need the 'one' in front of it. The same goes for 100 (백) and 1,000 (천). Don't say 일백 unless you are being very formal. Also, watch out for the number 6 (육). When it follows certain sounds, the pronunciation can shift slightly. Yes, even native speakers mess this up when speaking fast. Just keep your vowels clear and you will be fine.

Native Korean numbers are for 'counting'. Sino-Korean numbers are for 'labeling' and 'measuring'. Native numbers only go up to 99. Sino-Korean numbers go up to infinity. If you need to say 150, you must use Sino-Korean. Native numbers feel more 'organic' and 'warm'. Sino-Korean numbers feel 'logical' and 'cold'. Imagine Native numbers are for your friends and family. Imagine Sino-Korean numbers are for your bank account and your boss. You use Native numbers for the hour because hours feel like 'chunks' of time. You use Sino-Korean for minutes because minutes are 'measurements'. It is a balance of two worlds.