Sino-Korean vs Native Numbers: Usage Rules
Korean has two number systems. Learn which one to use for time, age, counting, dates, and money.
Choosing between Sino-Korean (일, 이, 삼, ...) and native Korean (하나, 둘, 셋, ...) numbers is one of the most common rule confusions for learners. The split is not random — there are clear categorical rules. Sino-Korean for: dates, months, years, minutes, money, phone numbers, addresses, floors, grades. Native Korean for: hours, age, counting people and objects with counters.
A useful way to remember: 'when the number is the abstract part of a label' (date, price, room number), use Sino-Korean. 'When the number is concretely counting things' (how many cups, how old, how many people), use native Korean. The famous mixed case is time: 'three thirty' is 세 시 (native, for hour) 삼십 분 (Sino, for minutes). This mixed system makes telling time difficult for beginners but quickly becomes automatic with practice. Once the categorical rule clicks, the choice is no longer a guess but a quick lookup against the category.
고유어 숫자 (Native Korean Numbers) — When to Use
Use native Korean numbers (하나, 둘, 셋, 넷, 다섯…) for: hours (한 시, 두 시), age with 살 (한 살, 두 살), counting objects with most counters (한 개, 두 명, 세 잔). Note: 하나/둘/셋/넷 shorten to 한/두/세/네 before a counter.
한자어 숫자 (Sino-Korean Numbers) — When to Use
Use sino-Korean numbers (일, 이, 삼, 사, 오…) for: dates & months (일 월, 이 월), minutes (오 분, 십 분), money (천 원, 만 원), floor numbers (일 층, 이 층), phone numbers, and numbers above 99.
How It Works
The two number systems divide by domain, and the division is consistent enough to be learned as a list rather than felt intuitively.
Native Korean numbers handle counting with classifiers, hours, ages and small quantities of things: 세 개, 네 명, 여섯 시, 스무 살. These are situations where you are enumerating discrete items one at a time.
Sino-Korean numbers handle dates, months, minutes, money, floors, phone numbers, addresses, and any number above about ninety-nine: 이 월 십사 일, 오 분, 삼천 원, 이 층. These are situations where a number is being read off a system — a calendar, a clock face, a price tag, a building directory.
The clearest demonstration is telling the time, which mixes both within a single expression. The hour uses native numbers and the minutes use Sino-Korean: 여섯 시 삼십 분. There is no way to avoid this by choosing one system, and the mixture is obligatory rather than stylistic.
Age has a similar split in practice. 살 takes native numbers, so 스무 살, but the formal 세 used in official contexts takes Sino-Korean. Most conversation uses 살.
Japanese speakers have a genuine advantage here, since Japanese makes a comparable split between 和語 and 漢語 numerals in expressions like 一つ versus 一.
Where You'll Hear It
Making an appointment exercises both systems at once. 세 시 삼십 분에 만나요 uses native for the hour and Sino-Korean for the minutes, and this is the single most common place learners notice the split for the first time.
Shopping runs on Sino-Korean because prices are always read that way. 이거 얼마예요? followed by 만 오천 원이에요 is an exchange you will have daily, and since Korean groups large numbers by 만 rather than by thousands, learning to hear 만 오천 as 15,000 takes deliberate practice.
Addresses and buildings use Sino-Korean throughout. 삼 층 ('third floor') appears on every lift panel, and giving your address or reading a room number puts you squarely in Sino-Korean territory.
Age comes up early in Korean conversation because of the title system, so 스무 살, 스물다섯 살 and similar forms get used quickly. Note that the native numbers have their own irregularities above twenty — 스무 살 rather than 스물 살 — which is the kind of detail that only surfaces once you are using the numbers rather than reciting them.
Cultural & Language Note
The two number systems split by domain in ways that feel arbitrary until you notice the pattern: native numbers count things you can point at, Sino-Korean numbers handle abstractions and measurements. Hence hours are native (세 시) but minutes are Sino (삼십 분), because clock hours were counted long before minutes were measured. Japanese has a similar split between ひとつ・ふたつ and いち・に.
Common Mistakes to Avoid
The time expression is the classic trap: 세 시 삼십 분 mixes both systems in one phrase, and learners tend to make it consistent in one direction or the other. Ages use native numbers with 살, floors use Sino with 층, and money is always Sino. When unsure, note that anything borrowed from a Sino-Korean counter word almost always takes Sino numbers.
How to Practice This Lesson
Do not try to learn both systems as two parallel lists. Learn each one attached to its domain. Practise native numbers only with counters and hours; practise Sino-Korean only with money, dates and minutes. Keeping them in separate contexts prevents the interference that comes from drilling them side by side.
Tell the time out loud ten times a day for a week, using whatever the clock actually says. Because time forces the mixture, this single exercise trains the split more efficiently than any explanation.
For money, practise reading prices from real photos of Korean price tags or menus. The 만 grouping is the genuine obstacle, and the only way through it is repetition with realistic amounts until 만 오천 원 registers as a quantity rather than as a sum you have to compute.