Native Korean Numbers 1-99

Native Korean numbers are used for "counting" rather than "labeling." If you can see it and touch it, you probably use this system. The system is built on unique words for 1 through 10. Then, there are unique words for each "ten" (20, 30, 40, etc.). To make a number like 25, you simply stack them. You say the word for 20 and then the word for 5. It is very logical once you memorize the base words. However, there is a small twist. When these numbers are followed by a "counter" (a word like "bottle" or "person"), some of them change their shape. It's like a grammar costume change. This only happens to the numbers 1, 2, 3, 4, and 20. Your brain might feel like it has 50 tabs open right now. That is totally normal. Just remember: Native numbers are for quantities you can visualize.

1. 1First, memorize the basic building blocks from 1 to 10. These are 하나 (1), 둘 (2), 셋 (3), 넷 (4), 다섯 (5), 여섯 (6), 일곱 (7), 여덟 (8), 아홉 (9), and 열 (10).
2. 2Next, learn the unique words for the tens. 스물 is 20, 서른 is 30, 마흔 is 40, 쉰 is 50, 예순 is 60, 일흔 is 70, 여든 is 80, and 아흔 is 90.
3. 3Combine them to create any number up to 99. For example, 11 is 열하나 (10 + 1). 35 is 서른다섯 (30 + 5). 99 is 아흔아홉 (90 + 9).
4. 4Apply the "Short Form" rule when using counters. If a counter word follows, 하나 becomes 한, 둘 becomes 두, 셋 becomes 세, 넷 becomes 네, and 스물 becomes 스무. Think of these as the "lazy" versions that are easier to say quickly.

• Use these for your age. In Korea, age is very important. You will say 스물다섯 살 (25 years old).
• Use these for the "hour" when telling time. If it is 3:00, you say 세 시.
• Use these for counting people. You might say 친구 두 명 (two friends).
• Use these for counting animals. For example, 강아지 한 마리 (one puppy).
• Use these for general objects using the counter 개. Like 사과 다섯 개 (five apples).
• Use these when you are just counting out loud (1, 2, 3...) while exercising or playing hide and seek. It's like a rhythmic chant.

• Do not use these for minutes or seconds. Those use the Sino-Korean system. It's like a grammar traffic light; hours are Native, minutes are Sino.
• Do not use these for money. If something costs 1,000 won, you use Sino-Korean. Native numbers are too "heavy" for big math.
• Do not use these for dates. Years, months, and days all prefer the Sino-Korean system.
• Do not use these for phone numbers or room numbers. Those are just labels, not quantities you are counting.
• Do not use these for anything over 99. If you have 100 apples, you switch to 백 (Sino-Korean).

• Forgetting the short forms is the number one mistake. Saying 하나 개 sounds very clunky. Always use 한 개.
• Mixing up the tens is common. 서른 (30) and 마흔 (40) often get swapped by new learners. Think of 서른 as "thirty" starting with the same 's' sound.
• Using Native numbers for minutes. This is a classic trap. You might say 세 시 세 분 for 3:03, but it must be 세 시 삼 분. Yes, even native speakers mess this up when they are tired!
• Using 스물 instead of 스무 before a counter. Remember, 20 is a shape-shifter just like 1, 2, 3, and 4.

Native Korean numbers vs. Sino-Korean numbers is the big battle. Sino-Korean numbers (일, 이, 삼...) come from Chinese characters. They are used for math, measurements, and labels. Native numbers are "Pure Korean." They are used for the "soul" of the language—age, time, and physical items. If you are at a job interview, you use Native numbers for your age. If you are talking about your salary, you use Sino-Korean. It’s a balance. Think of Native numbers as warm and personal, while Sino-Korean numbers are cold and precise.