Korean Numbers 1-100: Two Counting Systems, Finally Clear

Korean runs two parallel number systems, and both are in constant everyday use:

• Sino-Korean numbers (한자어 수사) came from Chinese. They’re built from single syllables, they’re almost perfectly regular, and they go as high as you like — thousands, millions, billions.
• Native Korean numbers (고유어 수사) are the home-grown set. They’re longer, less regular, and they stop dead at 99.

English quietly does something similar. We count ‘one, two, three’, but we also say ‘primary, secondary, tertiary’ and ‘mono-, di-, tri-’ — two number vocabularies from two different sources, each attached to its own set of jobs. Korean just makes the split impossible to ignore, because both sets are ordinary words that a five-year-old uses.

There’s a practical consequence worth knowing before you start. Sino-Korean is the regular one and the one that handles anything large, so it takes almost no effort. The set you actually have to sit down and memorise is the native one — and it only runs to 99, which is a smaller job than it sounds.

Start here, because this set is close to free. Learn ten syllables and you can build everything up to 99 without learning a single new word:

• 1 — 일 (il)
• 2 — 이 (i)
• 3 — 삼 (sam)
• 4 — 사 (sa)
• 5 — 오 (o)
• 6 — 육 (yuk)
• 7 — 칠 (chil)
• 8 — 팔 (pal)
• 9 — 구 (gu)
• 10 — 십 (sip)

From ten upward it’s arithmetic written out loud. Teens are ‘ten plus something’, and the tens are ‘something times ten’:

• 11 — 십일 (ten-one)
• 15 — 십오 (ten-five)
• 20 — 이십 (two-ten)
• 27 — 이십칠 (two-ten-seven)
• 30 — 삼십, 40 — 사십, 50 — 오십
• 60 — 육십, 70 — 칠십, 80 — 팔십, 90 — 구십
• 99 — 구십구
• 100 — 백 (baek)

Note that 백 is just 백, not 일백 — you don’t say ‘one hundred’ the way English does. Above that: 천 (thousand) and 만 (ten thousand). That last one catches people out, because Korean groups large numbers in units of ten thousand rather than thousands, so 100,000 is 십만 (‘ten ten-thousands’) rather than ‘a hundred thousand’.

Two small details worth picking up early. Zero has two forms: 영 (yeong) for maths and scores, 공 (gong) for phone numbers. And 16 is written 십육 but pronounced closer to simnyuk — a sound change that also hits 26, 36 and so on, so it’s worth hearing once rather than reading about twice.

This is the set that needs real memorisation, because the words don’t derive from each other the way the Sino-Korean ones do:

• 1 — 하나 (hana)
• 2 — 둘 (dul)
• 3 — 셋 (set)
• 4 — 넷 (net)
• 5 — 다섯 (daseot)
• 6 — 여섯 (yeoseot)
• 7 — 일곱 (ilgop)
• 8 — 여덟 (yeodeol)
• 9 — 아홉 (ahop)
• 10 — 열 (yeol)

The tens are each their own separate word, and there is no pattern connecting them — this is the part you simply have to drill:

• 20 — 스물 (seumul)
• 30 — 서른 (seoreun)
• 40 — 마흔 (maheun)
• 50 — 쉰 (swin)
• 60 — 예순 (yesun)
• 70 — 일흔 (ilheun)
• 80 — 여든 (yeodeun)
• 90 — 아흔 (aheun)

Combining is straightforward once you have those: 11 is 열하나, 12 is 열둘, 25 is 스물다섯, 47 is 마흔일곱, 99 is 아흔아홉.

And then it stops. There is no native Korean word for 100 — at that point everybody switches to 백. That’s why the honest answer to ‘what are the Korean numbers 1 to 100?’ is that only one of the two systems actually gets you all the way there.

Here is the part that matters more than the memorisation. Using the wrong system is what marks someone out as a beginner far more than a shaky accent does.

Sino-Korean handles anything that behaves like a written figure:

• Dates — years, months and days: 2026년 8월 2일
• Money: 오천 원 (5,000 won)
• Phone numbers, addresses and room numbers
• Minutes and seconds: 삼십 분 (thirty minutes)
• Floors of a building: 삼층 (third floor)
• Weights, distances and measurements
• Anything above 99, and all arithmetic

Native Korean handles things you can point at and count:

• The hour on a clock: 세 시 (three o’clock)
• Age: 스물다섯 살 (twenty-five years old)
• Objects, people, animals, drinks — anything with a counter word
• Number of times something happens: 세 번 (three times)

The clock is where the two systems collide most famously. 3:30 is 세 시 삼십 분 — native for the hour, Sino-Korean for the minutes, in the same breath. It looks bizarre written down and becomes automatic surprisingly fast.

One cultural aside while you’re here: 사 (four) sounds the same as the Sino-Korean word for death, which is why some Korean lift panels label the fourth floor F instead of 4. It’s the same instinct behind missing thirteenth floors in the West.

You can’t usually just say ‘three’ in Korean and stop. Counting something needs a counter — a small word that says what kind of thing you’re counting, a bit like ‘two slices of bread’ or ‘three sheets of paper’ in English, except Korean does it for almost everything.

The ones you’ll use constantly:

• 개 — general objects. The safe default when you can’t remember the right one.
• 명 — people (the polite version is 분)
• 마리 — animals
• 잔 — cups and glasses of something
• 병 — bottles
• 권 — books
• 장 — flat things: paper, tickets, photos
• 대 — cars, phones, machines
• 살 — years of age
• 번 — times, as in occurrences

Now the rule that trips absolutely everyone up. When a native Korean number sits in front of a counter, the first four numbers and 20 change shape:

• 하나 → 한: 한 개 (one item)
• 둘 → 두: 두 명 (two people)
• 셋 → 세: 세 잔 (three cups)
• 넷 → 네: 네 권 (four books)
• 스물 → 스무: 스무 살 (twenty years old)

The rest stay as they are — 다섯 개, 여섯 명, 아홉 잔. Say ‘하나 개’ and you will be understood, but it will land the way ‘two mans’ lands in English.

A few counters take Sino-Korean numbers instead, and they’re the ones attached to figures rather than to objects: 분 (minutes), 원 (won), 층 (floors), 인분 (portions of food). Watch out for 번, which does both jobs: 세 번 is ‘three times’ with a native number, while 삼번 is ‘number three’ — a bus route or a room — with a Sino-Korean one.

Numbers are the part of a language where knowing and using are furthest apart. You can recite 하나 둘 셋 perfectly at your desk and still freeze when a barista asks how many cups. Recall has to get down to about half a second, and only pressure gets it there.

Three things that shorten the gap:

• Count real objects, out loud, in the room you’re in. Books on the shelf, cups in the sink, people on the bus. It forces you to pick a counter, which is the actual difficult bit.
• Read prices and times aloud as you meet them. Receipts, clocks, bus timetables. This drills the Sino/native split in the only place it ever really matters — at speed.
• Say your own age, phone number and birthday until they’re reflexes. They’re the three number facts a stranger is most likely to ask you for.

Then use them with somebody. Ordering two coffees, agreeing to meet at half past seven, saying how old you are — that’s where the hesitation gets burned off, and it’s the same reason speaking practice beats another hour of flashcards. CoffeeTalk pairs you with a native Korean speaker for exactly this kind of low-stakes back-and-forth, and numbers come up in almost every conversation whether you plan them or not.

If you’re building the rest of your basics at the same time, Korean greetings, thank-yous and the ways to say I love you all follow the same politeness logic that the number systems hint at — and you can pick your conversation topics to make sure they come up.